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NSAC Long Range Plan

- What is the structure of the nucleon?
- What is the structure of nucleonic matter?
- What are the properties of hot nuclear matter?
- What is the nuclear microphysics of the universe?
- What is to be the new Standard Model?

Neutrino physics

Precision measurements: -decay, -decay, parity violating electron scattering, EDM’s…

What can they teach us about the new Standard Model?

TheStandard Modelof particle physics is a triumph of late 20th century physics

- It provides a unified framework for 3 of 4 (known) forces of nature in context of renormalizable gauge theory

TheStandard Modelof particle physics is a triumph of late 20th century physics

- Utilizes a simple & elegant symmetry principle to organize what we’ve observed

TheStandard Modelof particle physics is a triumph of late 20th century physics

- Utilizes a simple & elegant symmetry principle to organize what we’ve observed

Scaling violations in DIS Asymptotic freedom R(e+e-) Heavy quark systems Drell-Yan

Strong (QCD)

TheStandard Modelof particle physics is a triumph of late 20th century physics

- Utilizes a simple & elegant symmetry principle to organize what we’ve observed

“Maximal” parity violation Conserved Vector Current CP-Violation in K, B mesons Quark flavor mixing Lepton universality…..

Electroweak (=weak + QED)

TheStandard Modelof particle physics is a triumph of late 20th century physics

- Most of its predictions have been confirmed

Parity violation in neutral current processes: deep inelastic scattering, atomic transitions

The Standard Modelof particle physics is a triumph of late 20th century physics

- Most of its predictions have been confirmed

Jl0

Jlg

JlY

JlZ

Neutral currents mix

TheStandard Modelof particle physics is a triumph of late 20th century physics

- Most of its predictions have been confirmed

- W, Z0

- 3rd fermion generation (CP violation, anomaly)

- Higgs boson

New particles should be found

Ultra cold neutrons

LANSCE, SNS, NIST

CERN

We need anew Standard ModelTwo frontiers in the search

Collider experiments (pp, e+e-, etc) at higher energies (E >> MZ)

Indirect searches at lower energies (E < MZ) but high precision

Particle, nuclear & atomic physics

High energy physics

- “Forbidden processes”

- Weak decays
- lepton scattering

SM Radiative Corrections & Precision Measurements

Defects in the Standard Model

An Example Scenario: Supersymmetry

Low-energy Probes of Supersymmetry

- “Forbidden processes”

- EDM’s
- 0nbb decay
- m !e, m !eg…

SM Radiative Corrections & Precision Measurements

Defects in the Standard Model

An Example Scenario: Supersymmetry

Low-energy Probes of Supersymmetry

TheFermi Theoryof weak decays gave a successful, leading-order account

Fermi’s theory could incorporatehigher order QED contributions

QED radiative corrections: finite

The Fermi theory has trouble withhigher order weak contributions

Weak radiative corrections: infinite

Can’t be absorbed through suitable re-definition of GFin HEFF

Finite

All radiative corrections can be incorporated in the Standard Model with afinitenumber of termsg

g

g

g

GFencodes the effects of all higher orderweak radiative correctionsDrm depends on parameters of particles inside loops

g

Comparingradiative corrections in different processes canprobeparticle spectrumDrm differs from DrZ

Comparingradiative corrections in different processes canprobeparticle spectrum

Precision measurements predicted a range for mt before top quark discovery

- mt >> mb !
- mt is consistent with that range
- It didn’t have to be that way

Radiative corrections

Direct Measurements

Stunning SM Success

Comparingradiative corrections in different processes canprobeparticle spectrumJ. Ellison, UCI

Agreement with SM at level of loop effects ~ 0.1%

Global Analysisc2 per dof = 25.5 / 15

M. Grunenwald

II.Why a “New Standard Model”?

- There is no unification in the early SM Universe
- The Fermi constant is inexplicably large
- There shouldn’t be this much visible matter
- There shouldn’t be this much invisible matter

Early universe

Standard Model

High energy desert

Weak scale

Planck scale

The early SM Universe had nounificationEarly universe

Standard Model

Gravity

A “near miss” for grand unification

High energy desert

Weak scale

Planck scale

The early SM Universe had nounificationEarly universe

Unification Neutrino mass Dark Matter

Standard Model

GF would shrink

High energy desert

Weak scale

Planck scale

The Fermi constant is too largeA smaller GF would mean disaster

The Sun would burn less brightly

G ~ GF2

Elemental abundances would change

Tfreeze out ~ GF-2/3

SM baryogenesis

There is too much matter -visible & invisible - in the SM UniverseVisible Matter from Big Bang Nucleosynthesis

Insufficient CP violation in SM

Dark

Insufficient SM CP violation

Visible

There is too much matter -visible & invisible - in the SM UniverseInvisible Matter

S. Perlmutter

There must have been additional symmetries in the earlier Universe to

- Unify all forces
- Protect GF from shrinking
- Produce all the matter that exists

- Account for neutrino properties
- Give self-consistent quantum gravity

III.Supersymmetry

- Unify all forces
- Protect GF from shrinking
- Produce all the matter that exists

3 of 4

Yes

Maybe so

- Account for neutrino properties
- Give self-consistent quantum gravity

Maybe

Probably necessary

Bosons

sfermions

gauginos

Higgsinos

Charginos, neutralinos

SUSY may be one of the symmetries of the early UniverseSupersymmetry

Early universe

Standard Model

High energy desert

Weak scale

Planck scale

Couplings unify with SUSYSupersymmetry

CP Violation

Unbroken phase

Broken phase

SUSY may help explain observed abundance of matterCold Dark Matter Candidate

Baryonic matter

Superpartners have not been seen

Theoretical models of SUSY breaking

Visible World

Hidden World

Flavor-blind mediation

SUSY must be a broken symmetryLSM

+

LSUSY

+

Lsoft

Minimal Supersymmetric Standard Model (MSSM)Lsoft gives

contains 105 new parameters

How is SUSY broken?

Hidden Sector: SUSY-breaking

MSSM

Flavor-blind mediation

How is SUSY broken?

Gravity-Mediated (mSUGRA)

Hidden Sector: SUSY-breaking

MSSM

messengers

How is SUSY broken?

Flavor-blind mediation

Gauge-Mediated (GMSB)

gaugino mass

group structure

increases as

decreases

increases faster than

at the weak scale

Mass evolution

MSSM and R Parity

MSSM conserves

vertices have even number of superpartners

Consequences

- Lightest SUSY particle

is stable

viable dark matter candidate

- Proton is stable

- Superpartners appear only in loops

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