14.1 Early Discoveries 14.2 The Fundamental Interactions 14.8 Accelerators 14.3 Classification of Elementary Particles 1

1. 14.1 Early Discoveries 14.2 The Fundamental Interactions 14.8 Accelerators 14.3 Classification of Elementary Particles 14.4 Conservation Laws and Symmetries 14.5 Quarks 14.6 The Families of Matter 14.7 Beyond the Standard Model

2. Elementary Particles Finding answers to some of the basic questions about nature is a foremost goal of science: What are the basic building blocks of matter? What�s inside the nucleus? What are the forces that hold matter together? How did the universe begin? Will the universe end, and if so, how and when? http://www.lbl.gov/Science-Articles/Archive/sabl/2005/February/assets/ILC_LHC_vs_ILC_events.jpghttp://www.lbl.gov/Science-Articles/Archive/sabl/2005/February/assets/ILC_LHC_vs_ILC_events.jpg

3. 14.1: Early Discoveries Thomson had identified the electron in 1897, and Einstein had defined the photon in 1905. The proton is the nucleus of the hydrogen atom (let�s give Rutherford credit for its discovery). Despite the rapid progress of physics in the first couple of decades of the twentieth century, no more elementary particles were discovered until 1932, when James Chadwick identified the neutron first seen by Bothe and Becker. That seemed sufficient� In 1932, Irene Joliot-Curie, one of Madame Curie�s daughters, and her husband, Frederic Joliot-Curie, decided to use their strong polonium alpha source to further investigate Bothe�s penetrating radiation. They found that this radiation ejected protons from a paraffin target. This discovery was amazing because photons have no mass. However, the Joliot-Curies interpreted the results as the action of photons on the hydrogen atoms in paraffin. They used the analogy of the Compton Effect, in which photons impinging on a metal surface eject electrons. The trouble was that the electron was 1,836 times lighter than the proton and, therefore, recoiled much more easily than the heavier proton after a collision with a gamma photon. We now know that gamma photons do not have enough energy to eject protons from paraffin. When James Chadwick reported to Lord Rutherford on the Joliot-Curies� results, Lord Rutherford exclaimed, "I do not believe it!" Chadwick immediately repeated the experiments at the Cavendish Laboratory in Cambridge, England. He not only bombarded the hydrogen atoms in paraffin with the beryllium emissions, but also used helium, nitrogen, and other elements as targets. By comparing the energies of recoiling charged particles from different targets, he proved that the beryllium emissions contained a neutral component with a mass approximately equal to that of the proton. He called it the neutron in a paper published in the February 17, 1932, issue of Nature. In 1935, Sir James Chadwick received the Nobel Prize in physics for this work. You can read his lecture as he received his Nobel prize. It is interesting to note that the Joliot-Curies� misinterpretation of their results cost them the Nobel Prize. (Not to worry; in 1935, they received the Nobel Prize in chemistry for their discovery of artificial radioactivity.) Above text from: http://www.chemcases.com/nuclear/nc-01.htm Image from http://www.universetoday.com/74027/what-are-photons/ In 1932, Irene Joliot-Curie, one of Madame Curie�s daughters, and her husband, Frederic Joliot-Curie, decided to use their strong polonium alpha source to further investigate Bothe�s penetrating radiation. They found that this radiation ejected protons from a paraffin target. This discovery was amazing because photons have no mass. However, the Joliot-Curies interpreted the results as the action of photons on the hydrogen atoms in paraffin. They used the analogy of the Compton Effect, in which photons impinging on a metal surface eject electrons. The trouble was that the electron was 1,836 times lighter than the proton and, therefore, recoiled much more easily than the heavier proton after a collision with a gamma photon. We now know that gamma photons do not have enough energy to eject protons from paraffin. When James Chadwick reported to Lord Rutherford on the Joliot-Curies� results, Lord Rutherford exclaimed, "I do not believe it!" Chadwick immediately repeated the experiments at the Cavendish Laboratory in Cambridge, England. He not only bombarded the hydrogen atoms in paraffin with the beryllium emissions, but also used helium, nitrogen, and other elements as targets. By comparing the energies of recoiling charged particles from different targets, he proved that the beryllium emissions contained a neutral component with a mass approximately equal to that of the proton. He called it the neutron in a paper published in the February 17, 1932, issue of Nature. In 1935, Sir James Chadwick received the Nobel Prize in physics for this work. You can read his lecture as he received his Nobel prize. It is interesting to note that the Joliot-Curies� misinterpretation of their results cost them the Nobel Prize. (Not to worry; in 1935, they received the Nobel Prize in chemistry for their discovery of artificial radioactivity.) Above text from: http://www.chemcases.com/nuclear/nc-01.htm Image from http://www.universetoday.com/74027/what-are-photons/

4. The Positron In 1928 when Dirac combined quantum mechanics with special relativity, he introduced the relativistic theory of the electron. He found that, in free space, his wave equation had negative, as well as positive, energy solutions. His theory can be interpreted as the vacuum being filled with an infinite sea of electrons with negative energies. Exciting an electron from the �sea,� leaves behind a hole with negative energy, that is, the positron, denoted by e+. Photo of Dirac: http://images.google.com/imgres?imgurl=http://epress.anu.edu.au/maverick/html/fig-3-1.jpg&imgrefurl=http://epress.anu.edu.au/maverick/mobile_devices/ch03.html&h=388&w=300&sz=14&hl=en&start=1&um=1&tbnid=1qSjUNOIRbLizM:&tbnh=123&tbnw=95&prev=/images%3Fq%3Dpaul%2Bdirac%26um%3D1%26hl%3Den%26rlz%3D1T4GFRC_enUS212US212 Other is from TRex.Photo of Dirac: http://images.google.com/imgres?imgurl=http://epress.anu.edu.au/maverick/html/fig-3-1.jpg&imgrefurl=http://epress.anu.edu.au/maverick/mobile_devices/ch03.html&h=388&w=300&sz=14&hl=en&start=1&um=1&tbnid=1qSjUNOIRbLizM:&tbnh=123&tbnw=95&prev=/images%3Fq%3Dpaul%2Bdirac%26um%3D1%26hl%3Den%26rlz%3D1T4GFRC_enUS212US212 Other is from TRex.

5. Anti-particles Dirac�s theory yields anti-particles, which: Have the same mass and lifetime as their associated particles. Have the same magnitude but opposite sign for such physical quantities as electric charge and various quantum numbers. http://www.iop.org/activity/education/Teaching_Resources/Teaching%20Advanced%20Physics/Atomic%20and%20Nuclei/Images%20500/img_tb_5368.gifhttp://www.iop.org/activity/education/Teaching_Resources/Teaching%20Advanced%20Physics/Atomic%20and%20Nuclei/Images%20500/img_tb_5368.gif

6. Bubble chambers Image from wikipediaImage from wikipedia

7. Bubble chambers

8. Cloud chambers Image from http://www.science-project.com/projects/AstroPhysProj.shtml http://www.imperial.ac.uk/physics/asp/inside/index.asp Image from http://www.science-project.com/projects/AstroPhysProj.shtml http://www.imperial.ac.uk/physics/asp/inside/index.asp

9. Spark, drift, and time-projection chambers Image from Wikipedia and http://x-journals.com/2009/nimbus-open-source-cloud-computing-infrastructure-proves-its-worth/ Image from Wikipedia and http://x-journals.com/2009/nimbus-open-source-cloud-computing-infrastructure-proves-its-worth/

10. The Positron Carl Anderson identified the positron in cosmic rays. It was easy: it had positive charge and was light. Photo of particle track: http://athena-positrons.web.cern.ch/ATHENA-positrons/wwwathena/graphics/anderson-positron.jpg Other is from TRex.Photo of particle track: http://athena-positrons.web.cern.ch/ATHENA-positrons/wwwathena/graphics/anderson-positron.jpg Other is from TRex.

11. Positron-Electron Interaction The ultimate fate of positrons (anti-electrons) is annihilation with electrons. After a positron slows down by passing through matter, it�s attracted by the Coulomb force to an electron, where it is annihilated through the reaction:

12. Feynman Diagrams Richard Feynman presented a particularly simple graphical technique to describe particle interactions in quantum field theory. It predicts that, when two charged particles interact, they exchange a series of photons called virtual photons, which cannot be directly observed. Electromagnetism can be interpreted as the exchange of virtual photons. We say that the photons are the carriers or mediators of the electromagnetic force.

13. Yukawa�s Meson The Japanese physicist Hideki Yukawa had the idea of developing a quantum field theory that would describe the force between nucleons�analogous to the electromagnetic force. To do this, he had to determine the carrier or mediator of the nuclear strong force analogous to the photon in the electromagnetic force, which he called a meson (derived from the Greek word meso meaning �middle� due to its mass being between the electron and proton masses).

14. The mass of a mediator particle and the range of the force

15. Yukawa�s meson, called a pion (or pi-meson or p-meson), was identified in 1947 by C. F. Powell (1903�1969) and G. P. Occhialini (1907�1993) in cosmic rays at sites located at high altitude mountains, first at�Pic du Midi de Bigorre�in the�Pyrenees, and later at�Chacaltaya�in the Andes Mountains. Charged pions have masses of 140 MeV/c2, and a neutral pion p0 was later discovered that has a mass of 135 MeV/c2. Yukawa�s Meson

16. 14.8 Accelerators

17. Accelerators There are several types of accelerators used presently in particle physics experiments: cyclotrons, linear accelerators, and colliders. http://www.physics.carleton.ca/research/ilc/images/DE0061H.jpghttp://www.physics.carleton.ca/research/ilc/images/DE0061H.jpg

18. Cyclotrons and Synchrotrons electromagnetic energy called synchrotron radiation. This problem is particularly severe when electrons, moving very close to the speed of light, move in highly curved paths. If the radius of curvature is small, electrons can radiate as much energy as they gain. Physicists have learned to take advantage of these synchrotron radiation losses and now build special electron accelerators (called light sources) that produce copious amounts of photon radiation used for both basic and applied research. http://www.sync.monash.edu.au/assets/images/synchrotron.jpghttp://www.sync.monash.edu.au/assets/images/synchrotron.jpg

19. Linear Accelerators Linear accelerators or linacs typically have straight electric-field-free regions between gaps of RF voltage boosts. The particles gain speed with each boost, and the voltage boost is on for a fixed period of time, so the distance between gaps becomes increasingly larger as the particles accelerate. Linacs are sometimes used as pre-acceleration device for large circular accelerators. http://images.google.com/imgres?imgurl=http://www.lbl.gov/Science-Articles/Archive/sabl/2005/February/assets/ILC_LHC_vs_ILC_events.jpg&imgrefurl=http://www.lbl.gov/Science-Articles/Archive/sabl/2005/February/ILC.html&h=307&w=600&sz=181&hl=en&start=14&um=1&tbnid=dBm6Kr4OvGPNXM:&tbnh=69&tbnw=135&prev=/images%3Fq%3Dleptons%26um%3D1%26hl%3Den%26rlz%3D1T4GFRC_enUS212US212%26sa%3DN http://images.google.com/imgres?imgurl=http://www.lbl.gov/Science-Articles/Archive/sabl/2005/February/assets/ILC_LHC_vs_ILC_events.jpg&imgrefurl=http://www.lbl.gov/Science-Articles/Archive/sabl/2005/February/ILC.html&h=307&w=600&sz=181&hl=en&start=14&um=1&tbnid=dBm6Kr4OvGPNXM:&tbnh=69&tbnw=135&prev=/images%3Fq%3Dleptons%26um%3D1%26hl%3Den%26rlz%3D1T4GFRC_enUS212US212%26sa%3DN

20. Colliders Because of the limited energy available for reactions like that of the Tevatron, physicists began building colliding beam accelerators, in which the particles meet head-on. If the colliding particles have equal masses and kinetic energies, the total momentum is zero and all the energy is available for the reaction and the creation of new particles. www.physics.carleton.ca/research/ilc/tpc2.html www.physics.carleton.ca/research/ilc/tpc2.html

21. Large Hadron Collider Wikipedia: The Large Hadron Collider (LHC) is a particle accelerator located at CERN, near Geneva, Switzerland. It lies in a tunnel under France and Switzerland. It is currently in the final stages of construction, and commissioning, with some sections already being cooled down to its final operating temperature of ~2K (-271�C). The first beams are due for injection mid June 2008 with the first collisions planned to take place 2 months later.[1] The LHC will become the world's largest and highest-energy particle accelerator.[2] The LHC is being funded and built in collaboration with over two thousand physicists from thirty-four countries as well as hundreds of universities and laboratories. When activated, it is theorized that the collider will produce the elusive Higgs boson, the observation of which could confirm the predictions and "missing links" in the Standard Model of physics and could explain how other elementary particles acquire properties such as mass.[3][2] The verification of the existence of the Higgs boson would be a significant step in the search for a Grand Unified Theory, which seeks to unify the three fundamental forces: electromagnetism, the strong nuclear force and the weak nuclear force. The Higgs boson may also help to explain why gravitation is so weak compared to the other three forces. In addition to the Higgs boson, other theorized novel particles that might be produced, and for which searches[4] are planned, include strangelets, micro black holes, magnetic monopoles and supersymmetric particles.[5] The collider is contained in a circular tunnel with a circumference of 27�kilometres (17�mi) at a depth ranging from 50 to 175 metres underground.[6] The tunnel, constructed between 1983 and 1988,[7] was formerly used to house the LEP, an electron-positron collider. The 3.8 metre diameter, concrete-lined tunnel crosses the border between Switzerland and France at four points, although the majority of its length is inside France. The collider itself is located underground, with many surface buildings holding ancillary equipment such as compressors, ventilation equipment, control electronics and refrigeration plants. The collider tunnel contains two pipes enclosed within superconducting magnets cooled by liquid helium, each pipe containing a proton beam. The two beams travel in opposite directions around the ring. Additional magnets are used to direct the beams to four intersection points where interactions between them will take place. In total, over 1600 superconducting magnets are installed, with most weighing over 27 tonnes. The protons will each have an energy of 7 TeV, giving a total collision energy of 14 TeV. It will take around ninety microseconds for an individual proton to travel once around the collider. Rather than continuous beams, the protons will be "bunched" together, into approximately 2,800 bunches, so that interactions between the two beams will take place at discrete intervals never shorter than twenty-five nanoseconds apart. When the collider is first commissioned, it will be operated with fewer bunches, to give a bunch crossing interval of seventy-five nanoseconds. The number of bunches will later be increased to give a final bunch crossing interval of twenty-five nanoseconds.[citation needed] LHC Accelerators Prior to being injected into the main accelerator, the particles are prepared through a series of systems that successively increase the particle energy levels. The first system is the linear accelerator generating 50 MeV protons which feeds the Proton Synchrotron Booster (PSB). Protons are then injected at 1.4 GeV into the Proton Synchrotron (PS) at 26 GeV. Finally the Super Proton Synchrotron (SPS) can be used to increase the energy of protons up to 450 GeV. The ions will be first accelerated by the linear accelerator Linac 3, and the Low-Energy Injector Ring (LEIR) will be used as an ion storage and cooler unit. The ions are then further accelerated by the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS). Six detectors are being constructed at the LHC. They are located underground, in large caverns excavated at the LHC's intersection points. Two of them, ATLAS and CMS, are large, "general purpose" particle detectors.[2] ALICE is a large detector designed to search for a quark-gluon plasma in the very messy debris of heavy ion collisions. The other three (LHCb, TOTEM, and LHCf) are smaller and more specialized. A seventh experiment, (Forward Physics at 420m), has been proposed which would add detectors to four available spaces located 420m on either side of the ATLAS and CMS detectors.[8] The size of the LHC constitutes an exceptional engineering challenge with unique safety issues. While running, the total energy stored in the magnets is 10 GJ, and in the beam 725 MJ. Loss of only 10-7 of the beam is sufficient to quench a superconducting magnet, while the beam dump must absorb an energy equivalent to a typical air-dropped bomb. For comparison, 725 MJ is equivalent to the detonation energy of approximately 157�kilograms (350�lb) of TNT, and 10 GJ is about 2.5 tons of TNT. Research A Feynman diagram of one way the Higgs boson may be produced at the LHC. Here, two quarks each emit a W or Z boson which combine to make a neutral Higgs. A simulated event in the CMS detector, featuring the appearance of the Higgs boson. When in operation, about seven thousand scientists from eighty countries will have access to the LHC, the largest national contingent of seven hundred being from the United States. Physicists hope to use the collider to test various grand unified theories and enhance their ability to answer the following questions: Is the popular Higgs mechanism for generating elementary particle masses in the Standard Model realised in nature? If so, how many Higgs bosons are there, and what are their masses?[9] Will the more precise measurements of the masses of the quarks continue to be mutually consistent within the Standard Model? Do particles have supersymmetric ("SUSY") partners?[2] Why are there apparent violations of the symmetry between matter and antimatter?[2] See also CP-violation. Are there extra dimensions indicated by theoretical gravitons, as predicted by various models inspired by string theory, and can we "see" them? What is the nature of dark matter and dark energy?[2] Why is gravity so many orders of magnitude weaker than the other three fundamental forces? As an ion collider The LHC physics program is mainly based on proton-proton collisions. However, shorter running periods, typically one month per year, with heavy-ion collisions are included in the programme. While lighter ions are considered as well, the baseline scheme deals with lead (Pb) ions.[10] This will allow an advancement in the experimental programme currently in progress at the Relativistic Heavy Ion Collider (RHIC). Proposed upgrade CMS detector for LHC After some years of running, any particle physics experiment typically begins to suffer from diminishing returns; each additional year of operation discovers less than the year before. The way around the diminishing returns is to upgrade the experiment, either in energy or in luminosity. A luminosity upgrade of the LHC, called the Super LHC, has been proposed,[11] to be made after ten years of LHC operation. The optimal path for the LHC luminosity upgrade includes an increase in the beam current (i.e., the number of protons in the beams) and the modification of the two high luminosity interaction regions, ATLAS and CMS. To achieve these increases, the energy of the beams at the point that they are injected into the (Super) LHC should also be increased to 1 TeV. This will require an upgrade of the full pre-injector system, the needed changes in the Super Proton Synchrotron being the most expensive. Cost The construction of LHC was originally approved in 1995 with a budget of 2.6 billion Swiss francs, with another 210 million francs (140 M�) towards the cost of the experiments. However, cost over-runs, estimated in a major review in 2001 at around 480 million francs (300 M�) in the accelerator, and 50 million francs (30 M�) for the experiments, along with a reduction in CERN's budget pushed the completion date out from 2005 to April 2007.[12] 180 million francs (120 M�) of the cost increase has been the superconducting magnets. There were also engineering difficulties encountered while building the underground cavern for the Compact Muon Solenoid, due to, in part, the allegedly "faulty" parts lent to CERN by fellow laboratory and home to the world's largest particle accelerator, (until CERN finishes the Large Hadron Collider) Argonne National Laboratory, or FermiLab, located in Batavia, Illinois, outside of Chicago.[13] The total cost of the project is anticipated to be between $5 and $10 billion (US Dollars).[2]Wikipedia: The Large Hadron Collider (LHC) is a particle accelerator located at CERN, near Geneva, Switzerland. It lies in a tunnel under France and Switzerland. It is currently in the final stages of construction, and commissioning, with some sections already being cooled down to its final operating temperature of ~2K (-271�C). The first beams are due for injection mid June 2008 with the first collisions planned to take place 2 months later.[1] The LHC will become the world's largest and highest-energy particle accelerator.[2] The LHC is being funded and built in collaboration with over two thousand physicists from thirty-four countries as well as hundreds of universities and laboratories. When activated, it is theorized that the collider will produce the elusive Higgs boson, the observation of which could confirm the predictions and "missing links" in the Standard Model of physics and could explain how other elementary particles acquire properties such as mass.[3][2] The verification of the existence of the Higgs boson would be a significant step in the search for a Grand Unified Theory, which seeks to unify the three fundamental forces: electromagnetism, the strong nuclear force and the weak nuclear force. The Higgs boson may also help to explain why gravitation is so weak compared to the other three forces. In addition to the Higgs boson, other theorized novel particles that might be produced, and for which searches[4] are planned, include strangelets, micro black holes, magnetic monopoles and supersymmetric particles.[5] The collider is contained in a circular tunnel with a circumference of 27�kilometres (17�mi) at a depth ranging from 50 to 175 metres underground.[6] The tunnel, constructed between 1983 and 1988,[7] was formerly used to house the LEP, an electron-positron collider. The 3.8 metre diameter, concrete-lined tunnel crosses the border between Switzerland and France at four points, although the majority of its length is inside France. The collider itself is located underground, with many surface buildings holding ancillary equipment such as compressors, ventilation equipment, control electronics and refrigeration plants. The collider tunnel contains two pipes enclosed within superconducting magnets cooled by liquid helium, each pipe containing a proton beam. The two beams travel in opposite directions around the ring. Additional magnets are used to direct the beams to four intersection points where interactions between them will take place. In total, over 1600 superconducting magnets are installed, with most weighing over 27 tonnes. The protons will each have an energy of 7 TeV, giving a total collision energy of 14 TeV. It will take around ninety microseconds for an individual proton to travel once around the collider. Rather than continuous beams, the protons will be "bunched" together, into approximately 2,800 bunches, so that interactions between the two beams will take place at discrete intervals never shorter than twenty-five nanoseconds apart. When the collider is first commissioned, it will be operated with fewer bunches, to give a bunch crossing interval of seventy-five nanoseconds. The number of bunches will later be increased to give a final bunch crossing interval of twenty-five nanoseconds.[citation needed] LHC Accelerators Prior to being injected into the main accelerator, the particles are prepared through a series of systems that successively increase the particle energy levels. The first system is the linear accelerator generating 50 MeV protons which feeds the Proton Synchrotron Booster (PSB). Protons are then injected at 1.4 GeV into the Proton Synchrotron (PS) at 26 GeV. Finally the Super Proton Synchrotron (SPS) can be used to increase the energy of protons up to 450 GeV. The ions will be first accelerated by the linear accelerator Linac 3, and the Low-Energy Injector Ring (LEIR) will be used as an ion storage and cooler unit. The ions are then further accelerated by the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS). Six detectors are being constructed at the LHC. They are located underground, in large caverns excavated at the LHC's intersection points. Two of them, ATLAS and CMS, are large, "general purpose" particle detectors.[2] ALICE is a large detector designed to search for a quark-gluon plasma in the very messy debris of heavy ion collisions. The other three (LHCb, TOTEM, and LHCf) are smaller and more specialized. A seventh experiment, (Forward Physics at 420m), has been proposed which would add detectors to four available spaces located 420m on either side of the ATLAS and CMS detectors.[8] The size of the LHC constitutes an exceptional engineering challenge with unique safety issues. While running, the total energy stored in the magnets is 10 GJ, and in the beam 725 MJ. Loss of only 10-7 of the beam is sufficient to quench a superconducting magnet, while the beam dump must absorb an energy equivalent to a typical air-dropped bomb. For comparison, 725 MJ is equivalent to the detonation energy of approximately 157�kilograms (350�lb) of TNT, and 10 GJ is about 2.5 tons of TNT. Research A Feynman diagram of one way the Higgs boson may be produced at the LHC. Here, two quarks each emit a W or Z boson which combine to make a neutral Higgs. A simulated event in the CMS detector, featuring the appearance of the Higgs boson. When in operation, about seven thousand scientists from eighty countries will have access to the LHC, the largest national contingent of seven hundred being from the United States. Physicists hope to use the collider to test various grand unified theories and enhance their ability to answer the following questions: Is the popular Higgs mechanism for generating elementary particle masses in the Standard Model realised in nature? If so, how many Higgs bosons are there, and what are their masses?[9] Will the more precise measurements of the masses of the quarks continue to be mutually consistent within the Standard Model? Do particles have supersymmetric ("SUSY") partners?[2] Why are there apparent violations of the symmetry between matter and antimatter?[2] See also CP-violation. Are there extra dimensions indicated by theoretical gravitons, as predicted by various models inspired by string theory, and can we "see" them? What is the nature of dark matter and dark energy?[2] Why is gravity so many orders of magnitude weaker than the other three fundamental forces? As an ion collider The LHC physics program is mainly based on proton-proton collisions. However, shorter running periods, typically one month per year, with heavy-ion collisions are included in the programme. While lighter ions are considered as well, the baseline scheme deals with lead (Pb) ions.[10] This will allow an advancement in the experimental programme currently in progress at the Relativistic Heavy Ion Collider (RHIC). Proposed upgrade CMS detector for LHC After some years of running, any particle physics experiment typically begins to suffer from diminishing returns; each additional year of operation discovers less than the year before. The way around the diminishing returns is to upgrade the experiment, either in energy or in luminosity. A luminosity upgrade of the LHC, called the Super LHC, has been proposed,[11] to be made after ten years of LHC operation. The optimal path for the LHC luminosity upgrade includes an increase in the beam current (i.e., the number of protons in the beams) and the modification of the two high luminosity interaction regions, ATLAS and CMS. To achieve these increases, the energy of the beams at the point that they are injected into the (Super) LHC should also be increased to 1 TeV. This will require an upgrade of the full pre-injector system, the needed changes in the Super Proton Synchrotron being the most expensive. Cost The construction of LHC was originally approved in 1995 with a budget of 2.6 billion Swiss francs, with another 210 million francs (140 M�) towards the cost of the experiments. However, cost over-runs, estimated in a major review in 2001 at around 480 million francs (300 M�) in the accelerator, and 50 million francs (30 M�) for the experiments, along with a reduction in CERN's budget pushed the completion date out from 2005 to April 2007.[12] 180 million francs (120 M�) of the cost increase has been the superconducting magnets. There were also engineering difficulties encountered while building the underground cavern for the Compact Muon Solenoid, due to, in part, the allegedly "faulty" parts lent to CERN by fellow laboratory and home to the world's largest particle accelerator, (until CERN finishes the Large Hadron Collider) Argonne National Laboratory, or FermiLab, located in Batavia, Illinois, outside of Chicago.[13] The total cost of the project is anticipated to be between $5 and $10 billion (US Dollars).[2]

22. The Weak Interaction In the 1960s Sheldon Glashow, Steven Weinberg, and Abdus Salam predicted that particles that they called W (for weak) and Z should exist that are responsible for the weak interaction. They have been observed in accelerators.

23. The Graviton It has been suggested that the particle responsible for the gravitational interaction be called a graviton. The graviton is the mediator of gravity in quantum field theory and has been postulated because of the success of the photon in quantum electrodynamics theory. It must be massless, travel at the speed of light, have spin 2, and interact with all particles that have mass-energy. The graviton has never been observed because of its extremely weak interaction with objects. http://www.enterprisemission.com/_articles/05-14-2004_Interplanetary_Part_1/Solar%20System.jpghttp://www.enterprisemission.com/_articles/05-14-2004_Interplanetary_Part_1/Solar%20System.jpg

24. Neutrinos Neutrinos have zero charge. The electron neutrino occurs in the beta decay of the neutron. Their masses are known to be very small. The precise mass of neutrinos may have a bearing on current cosmological theories of the universe because of the gravitational attraction of mass. Like all other leptons, they have spin 1/2, and all three neutrinos have been identified experimentally. Neutrinos are particularly difficult to detect because they have no charge and little mass, and they interact very weakly (they easily pass through the earth!). math.ucr.edu/home/baez/week242.html math.ucr.edu/home/baez/week242.html

25. Neutrino Oscillations One of the most perplexing problems over the last three decades has been the solar neutrino problem: the number of neutrinos reaching Earth from the sun is a factor of 2 to 3 too small if our understanding of the energy-producing (nuclear fusion) is correct. Neutrinos come in three varieties or flavors: electron, muon, and tau. The solution was found when researchers saw neutrinos generated in the Earth�s atmosphere (from cosmic rays) changing or �oscillating� into another flavor (the sun only emits electron neutrinos). Also, this could only happen if neutrinos have mass. http://content.answers.com/main/content/wp/en/thumb/8/83/400px-Electron_neutrino_oscillation_long.pnghttp://content.answers.com/main/content/wp/en/thumb/8/83/400px-Electron_neutrino_oscillation_long.png

26. Classifying Elementary Particles Particles with half-integral spin are called fermions and those with integral spin are called bosons. This is a particularly useful way to classify elementary particles because all stable matter in the universe appears to be composed, at some level, of constituent fermions. Fermions obey the Pauli Exclusion Principle. Bosons don�t.

27. Leptons: electrons, muons, taus & neutrinos The leptons are perhaps the simplest of the elementary particles. They appear to be point-like, that is, with no apparent internal structure, and seem to be truly elementary. http://www.tcd.ie/Physics/Schools/what/quarks/leptons.gifhttp://www.tcd.ie/Physics/Schools/what/quarks/leptons.gif

28. Muon and tau decay Even though they�re fundamental, the muon decays into an electron, and the tau can decay into an electron, a muon, or even hadrons. The muon decay (by the weak interaction) is: http://www.autodynamics.org/main/images/pagemaster/bubbleInvertedSmall.gif http://www.autodynamics.org/main/images/pagemaster/bubbleInvertedSmall.gif

29. Hadrons Hadrons are particles that act through the strong force. Two classes of hadrons: mesons and baryons. http://www.lepp.cornell.edu/public/lab-info/video/images/jpg/mesons.jpghttp://www.lepp.cornell.edu/public/lab-info/video/images/jpg/mesons.jpg

30. 14.4: Conservation Laws Physicists like to have clear rules or laws that determine whether a certain process can occur or not. It seems that everything occurs in nature that is not forbidden. Certain conservation laws are already familiar from our study of classical physics. These include mass-energy, charge, linear momentum, and angular momentum. These are absolute conservation laws: they are always obeyed.

31. Baryon Conservation In low-energy nuclear reactions, the number of nucleons is always conserved. Empirically this is part of a more general conservation law for what is assigned a new quantum number called baryon number that has the value B = +1 for baryons and -1 for anti-baryons, and 0 for all other particles (mesons, leptons). The conservation of baryon number requires the same total baryon number before and after the reaction. Although there are no known violations of baryon conservation, there are theoretical and observational indications that it was violated sometime in the beginning of the universe when temperatures were quite high. This is thought to account for the preponderance of matter over anti-matter in the universe today. Image from http://weblogs.marylandweather.com/2009/04/hubble_snaps_galaxy_triplets.html Image from http://weblogs.marylandweather.com/2009/04/hubble_snaps_galaxy_triplets.html

32. Lepton Conservation The leptons are all fundamental particles, and there is conservation of leptons for each of the three kinds (families) of leptons. The number of leptons from each family is the same both before and after a reaction. We let Le = +1 for the electron and the electron neutrino; Le = -1 for their antiparticles; and Le = 0 for all other particles. We assign the quantum numbers Lm for the muon and its neutrino and Lt for the tau and its neutrino similarly. Thus leptons give us three additional conservation laws. http://www.symmetrymagazine.org/images/200707/article07_image06.jpg http://www.symmetrymagazine.org/images/200707/article07_image06.jpg

33. Strangeness The behavior of the K-mesons is very odd. p0 mesons decay quickly into pairs of photons, but K0 mesons don�t. A new quantum number was defined: Strangeness, S, which is conserved in the strong and electromagnetic interactions, but not in the weak interaction. Image from http://www.topnews.in/people/boy-george Top image from http://www.labspaces.net/8960/Fermilab_physicists_discover__doubly_strange__particle Image from http://www.topnews.in/people/boy-george Top image from http://www.labspaces.net/8960/Fermilab_physicists_discover__doubly_strange__particle

34. Some Hadrons

35. A veritable zoo of particles! image from wikipedaiimage from wikipedai

36. Baryons and mesons revisited

37. Evidence for quarks Image from http://nobelprize.org/nobel_prizes/physics/laureates/1990/taylor.html Image from http://nobelprize.org/nobel_prizes/physics/laureates/1990/taylor.html

38. Truth, Beauty, and Charm And then a fourth quark called the charmed quark (c) was proposed to explain some additional discrepancies in the lifetimes of some of the known particles. A new quantum number called charm C was introduced so that the new quark would have C = +1 while its anti-quark would have C = -1 and particles without the charmed quark have C = 0. Charm is similar to strangeness in that it is conserved in the strong and electromagnetic interactions, but not in the weak interactions. This behavior was sufficient to explain the particle lifetime difficulties. Two additional quarks, top and bottom (or truth and beauty), were also required to construct some exotic particles (the Upsilon-meson).

39. Quark Properties http://www.jlab.org/~hleiqawi/6quarks.jpghttp://www.jlab.org/~hleiqawi/6quarks.jpg

40. Quark Description of Particles Baryons normally consist of three quarks or anti-quarks. A meson consists of a quark-anti-quark pair, yielding the required baryon number of 0.

41. A colorful mystery What about the quark composition of the W-, which has a strangeness of S = -3? Its quark composition is sss. Its charge is 3(-e/3) = -e, and its spin is due to three quark spins, all aligned: 3(1/2) = 3/2. Because all quarks have spin 1/2, they�re all fermions. According to the Pauli exclusion principle, no two fermions can exist in the same state. Yet we have three identical strange quarks in the W-! What�s going on?

42. Quantum Chromodynamics (QCD) This isn�t possible unless some other quantum number distinguishes each of these quarks in one particle. A new quantum number called color circumvents this problem and its properties establish Chromodynamics (QCD). The bubble chamber picture of the first omega-minus. An incoming K- meson interacts with a proton in the liquid hydrogen of the bubble chamber and produces an omega-minus, a K� and a K+ meson which all decay into other particles. Neutral particles which produce no tracks in the chamber are shown by dashed lines. The presence and properties of the neutral particles are established by analysis of the tracks of their charged decay products and application of the laws of conservation of mass and energy. The bubble chamber picture of the first omega-minus. An incoming K- meson interacts with a proton in the liquid hydrogen of the bubble chamber and produces an omega-minus, a K� and a K+ meson which all decay into other particles. Neutral particles which produce no tracks in the chamber are shown by dashed lines. The presence and properties of the neutral particles are established by analysis of the tracks of their charged decay products and application of the laws of conservation of mass and energy.

43. There are three colors for quarks we call red (R), green (G), and blue (B) with anti-quark color antired ( ); antigreen ( ) and antiblue ( ). (A bar above the symbol is usually used to describe the �anti-color�). Color is the �charge� of the strong nuclear force, analogous to charge for electromagnetism. Color http://www.rahul.net/raithel/otfw/Images/quarks.jpghttp://www.rahul.net/raithel/otfw/Images/quarks.jpg

44. Gluons The particle that mediates the very strong interaction between quarks is called a gluon (for the �glue� that holds the quarks together); it�s massless and has spin 1, just like the photon. http://images.google.com/imgres?imgurl=http://www.lactamme.polytechnique.fr/Mosaic/images/NUCL.LD.2.d.D/image.jpg&imgrefurl=http://www.lactamme.polytechnique.fr/Mosaic/images/NUCL.LD.2.d.D/display.html&h=512&w=512&sz=25&hl=en&start=7&um=1&tbnid=8q0T0Hlr2DJBJM:&tbnh=131&tbnw=131&prev=/images%3Fq%3Dgluon%26um%3D1%26hl%3Den%26rlz%3D1T4GFRC_enUS212US212%26sa%3DNhttp://images.google.com/imgres?imgurl=http://www.lactamme.polytechnique.fr/Mosaic/images/NUCL.LD.2.d.D/image.jpg&imgrefurl=http://www.lactamme.polytechnique.fr/Mosaic/images/NUCL.LD.2.d.D/display.html&h=512&w=512&sz=25&hl=en&start=7&um=1&tbnid=8q0T0Hlr2DJBJM:&tbnh=131&tbnw=131&prev=/images%3Fq%3Dgluon%26um%3D1%26hl%3Den%26rlz%3D1T4GFRC_enUS212US212%26sa%3DN

45. Quark-anti-quark creation No one�s ever measured a free quark. Physicists now believe that free quarks cannot be observed; they can only exist within hadrons. This is called confinement. This occurs because the force between the quarks increases rapidly with distance, and the energy supplied to separate them creates new quark-anti-quark pairs.

46. Fundamental and Composite Particles We call certain particles fundamental; this means that they aren�t composed of other, smaller particles. We believe leptons, quarks, and gauge bosons are fundamental particles. Other particles are composites, made from the fundamental particles. Some of these fundamental particles (W, Z, m, t) have short lifetimes and decay, but this is okay. http://www.eurekalert.org/multimedia/pub/web/4280_web.jpghttp://www.eurekalert.org/multimedia/pub/web/4280_web.jpg

47. The Families of Matter

48. The Four Fundamental Interactions

49. The Four Fundamental Interactions

50. Unifying all these interactions is hard.

51. Unifying the Electromagnetic and Weak forces: the Electroweak Theory In the 1960s, Sheldon Glashow, Steven Weinberg, and Abdus Salam unified the electromagnetic and weak interactions into what they called the electroweak theory.

52. Unification of the Strong and Electroweak Interactions: The Standard Model Over the latter half of the 20th century, numerous physicists combined efforts to generate The Standard Model. It is a widely accepted theory of elementary particle physics at present. It is a relatively simple, comprehensive theory that explains hundreds of particles and complex interactions with six quarks, six leptons, and three force-mediating particles. It is a combination of the electroweak theory and quantum chromodynamics (QCD), but does not include gravity.

53. Grand Unifying Theories (GUTs) Physicists feel that the standard model is inelegant (too many free parameters and coupling constants). Several grand unified theories (GUTs) now combine the weak, electromagnetic, and strong interactions and predict that, at extremely high energies (>1014 GeV), the electromagnetic, weak, and strong forces fuse into a single unified field. Currently, they can explain why: Neutrinos have a small, but finite, mass. The proton and electron charges have the same magnitude. Massive magnetic monopoles may exist. Just one anywhere in  the universe would explain charge quantization. But current experimental measurements have shown the proton lifetime to be greater than 1032 years. Current theory has it at 1029 to 1031 years. Wikipedia: Physicists feel that three independent gauge coupling constants and a huge number of Yukawa coupling coefficients require far too many free parameters, and that these coupling constants ought to be explained by a theory with fewer free parameters. A gauge theory where the gauge group is a simple group only has one gauge coupling constant, and since the fermions are now grouped together in larger representations, there are fewer Yukawa coupling coefficients as well. Wikipedia: Physicists feel that three independent gauge coupling constants and a huge number of Yukawa coupling coefficients require far too many free parameters, and that these coupling constants ought to be explained by a theory with fewer free parameters. A gauge theory where the gauge group is a simple group only has one gauge coupling constant, and since the fermions are now grouped together in larger representations, there are fewer Yukawa coupling coefficients as well.

54. The Standard Model of particle physics proposes that there is a field called the Higgs field that permeates all of space. By interacting with this field, particles acquire mass. Particles that interact strongly with the Higgs field have heavy mass; particles that interact weakly have small mass. Another boson has been predicted, but not yet detected, and is necessary in quantum field theory to explain why the W� and Z have such large masses, while the photon has no mass. This missing boson is called the Higgs particle (or Higgs boson) after Peter Higgs, who first proposed it. The Higgs boson is very heavy, and it hasn�t been observed yet. The search for the Higgs boson is of the highest priority in elementary particle physics. The Higgs Boson WikipediaWikipedia

55. Another challenge:Matter-Antimatter According to the Big Bang theory, matter and antimatter should have been created in exactly equal quantities. But it appears that matter dominates over antimatter now in our universe, and the reason for this has puzzled physicists and cosmologists for years. Events in the early universe may be responsible for this asymmetry. But explanations go far beyond the standard model. http://www.galaxyphoto.com/high_res/hst_galaxy.JPGhttp://www.galaxyphoto.com/high_res/hst_galaxy.JPG

56. Including Gravity: String Theory For the last two decades there has been a tremendous amount of effort by theorists in string theory, which has had several variations. The addition of super-symmetry resulted in the name theory of super-strings. In super-string theory, elementary particles don�t exist as points, but rather as tiny, wiggling loops that are only 10-35 m in length. Presently super-string theory is a promising approach to unify the four fundamental forces, including gravity. However, because experiments that can confirm or falsify string theory require orders of magnitude more energetic particles than can currently be produced, these theories are very controversial. http://woodside.blogs.com/cosmologycuriosity/images/2007/05/11/nova_pbs_elegant_universe_brian_gre.jpghttp://woodside.blogs.com/cosmologycuriosity/images/2007/05/11/nova_pbs_elegant_universe_brian_gre.jpg

57. Super-symmetry Super-symmetry is a necessary ingredient in many of the theories trying to unify all four forces of nature. The symmetry relates fermions and bosons. All fermions have a super-partner: a boson of equal mass, and vice versa. These particles include sleptons, squarks, axions, winos, photinos, zinos, gluinos, and preons. The super-partner spins differ by h/2. Presently, none of the known leptons, quarks, or gauge bosons can be identified with a super-partner of any other particle type. http://www.nasa.gov/images/content/188435main_DkMatter_med.jpghttp://www.nasa.gov/images/content/188435main_DkMatter_med.jpg

58. M-theory Recently theorists have proposed a successor to super-string theory called M-theory. M-theory has 11 dimensions (ten spatial and one temporal) and predicts that strings coexist with membranes, called �branes� for short. Only through experiments (which no one currently knows how to do, since they require > 1,000,000 times more energy than current accelerators can produce) will scientists be able to wade through the vast number of unifying theories. Background: http://www.maths.qmul.ac.uk/epstar/images/mtheory-cropped.jpg Membrane: http://upload.wikimedia.org/wikipedia/commons/d/d4/Calabi-Yau.png Background: http://www.maths.qmul.ac.uk/epstar/images/mtheory-cropped.jpg Membrane: http://upload.wikimedia.org/wikipedia/commons/d/d4/Calabi-Yau.png