1 / 15

B. I. Stepanov Institute of Physics National Academy of Sciences of Belarus

B. I. Stepanov Institute of Physics National Academy of Sciences of Belarus. Status of the magnetic monopoles in ATLAS. Yu. Kurochkin, Yu. Kulchitsky, I. Satsunkevich, N. Rusakovich, Dz. Shoukavy. Gomel , 200 7. CONTENTS. 1. Introduction and limits on the monopole mass. 2.

nadine-pena
Download Presentation

B. I. Stepanov Institute of Physics National Academy of Sciences of Belarus

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. B. I. Stepanov Institute of PhysicsNational Academy of Sciences ofBelarus

  2. Status of the magnetic monopoles in ATLAS Yu. Kurochkin, Yu. Kulchitsky, I. Satsunkevich, N. Rusakovich, Dz. Shoukavy Gomel, 2007

  3. CONTENTS 1 Introduction and limits on the monopole mass 2 Two photon vs. Drell-Yan 3 Signature 4 Conclusion and future plans Gomel, 2007

  4. Introduction WHYdoes quantisation of the electric charge exist? In 1931 Dirac showed that the existence of single magnetic monopole with magnetic charge g explained the quantization of electric charge e in terms of the Dirac quantization condition e g = n ħc/2(P.A.M. Dirac, 1931) minimummagnetic charge Besides explaining the quantization of electric charge, the existence of magnetic charges restores the symmetry of the Maxwell’s equations. Thus, existence of both electric and magnetic charge in the Universe requires charge quantization. Since the quantization of electric charge in nature is well established but still mysterious, the discovery of just a single monopole would provide a much wanted explanation. Gomel, 2007

  5. Introduction New situation was created in 1974 after work's Polyakov and 'tHooft in which they demonstrated monopole solutions in the SO(3) Georgi-Glashow model. Later it was discovered that any scheme of Grand Unification with an electromagnetic U(1) subgroup embedded into a semi-simple gauge group, which became spontaneously broken by Higgs mechanism, possessed monopole solutions inevitably. The monopoles of the usual Grand Unification have a mass of the order of the unification scale 1017 GeV and therefore cannot be discovered at the current or future accelerators. They could only be produced in the first instants of our Universe and can be searched for in the penetrating cosmic radiation. However, there are models of the Grand Unification where the electroweak symmetry breaking can give rise to monopoles of mass ~ 1 – 15 TeV . It was shown that the unification scale could be significantly lowered through appearance of extra dimensions. Gomel, 2007

  6. The experimental limits on monopole mass The most recent limits on the monopole mass HERA e+ p – collisions |n|=1,2,3,6 Tevatron p p – collisions Experiment E-882 (Al) |n|=1, M > 285 GeV (Al)|n|=2, M > 355 GeV (Be) |n|=3, M > 325 GeV (Be) |n|=6, M > 420 GeV LEP 2 e+ e-– collisions (Al) M > 140GeV 45 > M < 102GeV Drell - Yan mechanism M > 360 GeV CDF Run II Gomel, 2007

  7. The experimental limits on monopole mass The limits on the Dirac monopole mass which was obtained at the Tevatron (D0 collaboration) from the analysis of the process for γγ production via virtual monopole loop are strongly criticized and questioned1,2 (because the cross section violate unitarity ). 1.L. Gamberg, G.Kalbfleisch, K. Milton, Found. Phys.30, 543 (2000) 2.K. Milton, G. Kalbfleisch, W. Luo, L. Gamberg, Int. J. Mod.Phys. A 17, 732 (2002). Gomel, 2007

  8. Monopole production By a Dirac monopole we mean a particle without electric charge or hadronic interactions but with magnetic charge g satisfying the Dirac quantization. Going from lepton production we replace e gβ Two photon s=1/2 Drell-Yan Gomel,2007

  9. Cross section The comparison production cross section γ γfusion and Drell-Yan for monopole-antimonopole pair in pp-collisions at s =14 TeV The relative dominance vs. γ γfusion changes for monopoles So, two photon production is the leading mechanism for direct monopole searches at LHC Yu. Kurochkin et. al. On production of magnetic monopoles via γγ fusion at high energy pp-collisions / Mod.Phys. Lett. A, 21, 2873,2006. Gomel,2007

  10. Signature If magnetic monopoles produced in ATLAS then monopole would be revealed by its unique characteristics • Behavior of a monopole in a magnetic field. Because monopoles will be accelerated along an external magnetic field the trajectories of monopoles and ordinary charged particles differ considerably. • The large value of a magnetic charge means that ionization energy losses will be several orders of magnitude greater for monopoles than for electrically charged particle. • The large transition radiation. Gomel,2007

  11. Behavior of a monopole in a magnetic field While the trajectories of electrically charge particles curve is rφ plane, monopoles will curve in the rz plane. Monopole trajectory is a parabola, stretched by relativistic effect in the rz plane In the plane perpendicular to the magnetic field, the motion is in a straight line, in sharp contrast to electrically charged particles, which curve in this plane. Gomel,2007

  12. Energy loss by ionization The energy loss dE/dx due to ionization for an electrically charged particle is given Bethe-Bloch formula - isthe mean excitation energy of the scattering material For magnetic monopoles with velocities we need make the replacement The energy loss dE/dx due to ionization does not depend on the mass of the incident particle but just its kinematic properties Gomel, 2007

  13. Energy loss by ionization For example, comparison energy loss pion and monopole in neon Z=10 (Neon) Z=10 (Неон) Energy loss/cm: MeV-charged particles and GeV- monopoles • Since magnetic charge cannot simulated in GEANT directly, then magnetic monopoles were simulated as heavy electrically charged fermions with an effective charge ze=gβ(assuming n=1) Gomel,2007

  14. Transition Radiation As in ATLAS there is a detector of transition radiation, then we have additional opportunity for monopole search. The energy radiated when particle with charge ze crosses the boundary between vacuum and a medium plasma frequency ωp is The typical emission angle ~ 1/γ. For a particle with γ=103 the radiated photons are in the soft x-ray range 2 to 20 keV. The number of radiated photons For monopole we make the replacement Thus, for monopole will be some tens times more radiated photons Gomel,2007

  15. Conclusion and Plans • LHC will open a new era in search for magnetic monopoles of any nature. • GEANT is a widely used tool for detector description and simulation, but it has not particles with magnetic charge. • For reliable energy loss (and hence triggering possibility) need to take into account the energy gain inside Inner Detector by acceleration due to magnetic field. The main goal of the future works • We need write additional GEANT code for magnetic monopole and understand trigger conditions. Gomel,2007

More Related