Flavour Physics and Dark Matter

Introduction

Selected Experimental Results

Impact on Dark Matter Searches

Conclusion

Matthew HerndonUniversity of Wisconsin

Dark Side of the Universe 2007, Minneapolis Minnesota

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Why Beyond Standard Model?Standard Model predictions validated to high precision, however

Connection between collider based physics and

astrophysics becomes more interesting each year

M. Herndon

Gravity not a part of the SM

What is the very high energy

behaviour?

At the beginning of the universe?

Dark Matter?

Astronomical observations of indicate that

there is more matter than we see

Where is the Antimatter?

Why is the observed universe mostly matter?

Standard Model fails to answer many fundamental questions

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Many of those questions come from Astrophysics and Cosmology

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Searches For New PhysicsHow do you search for new physics at a collider?

Direct searches for production of new particles

Particle-antipartical annihilation: top quark

Indirect searches for evidence of new particles

Within a complex process new particles can occur virtually

Rare Decays, CP Violating Decays and Processes such as Mixing

Present unique opportunity to find new physicsM. Herndon

Tevatron is at the energy frontier

Tevatron and b factories are at a data volume frontier

billions B and Charm events on tape

So much data that we can look for some very unusual processes

Where to look

Many weak processes involving B hadrons are very low probability

Look for contributions from other low probability processes – Non Standard Model

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B Physics Beyond the SMLook at processes that are suppressed in the SM

Excellent place to spot small contributions from non SM contributions

The Main Players:

Bs(d) →μμ-

SM: No tree level decay

b s

Penguin decay

New Players

Bs Oscillations

B

M. Herndon

Same particles/vertices occur in both B decay diagrams

and in dark matter scattering or annihilation diagrams

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The B Factories

EXCELLENT MUON DETECTIONEXCELLENT TRACKING:

TIME RESOLUTIONEXCELLENT PARTICLE ID

CDF

D0

BABAR

BELLE

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b → sLook at decays that are suppressed in the

Standard Model: b → s

Classic b channel for searching for new physics

Inclusive decay easier to calculate but still difficult

New physics can enter into the

loop(penquin)

Decay observed

Now a matter of precision

measurement and precision

calculation of the SM rate

New calculation by Misiak et. al.

NNLO calucation - 17 authors

and 3 years of effort

BR(b → s) = 3.15 0.23 x 10-4

M. Herndon One of the best indirect search channels at the b factrories

PRL 98 022002 2007

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b → sMeasure the inclusive branching ratio from

the photon spectrum

Backgrounds from continuum production

and other B decaysContinuum backgrounds suppressed using event shapes or reconstruction the other B

o and reconstructed and suppressed

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Bs(d) → μ+μ-

Look at decays that are suppressed in the

Standard Model: Bs(d) →μμ-

Flavor changing neutral currents(FCNC) to leptons

No tree level decay in SM

Loop level transitions: suppressed

CKM , GIM and helicity(ml/mb): suppressed

SM: BF(Bs(d) →μμ-) = 3.5x10-9(1.0x10-10)G. Buchalla, A. Buras, Nucl. Phys. B398,285

New physics possibilities

Loop: MSSM: mSugra, Higgs Doublet

3 orders of magnitude enhancement

Rate tan6β/(MA)4

Babu and Kolda, Phys. Rev. Lett. 84, 228

Tree: R-Parity violating SUSY

Small theoretical uncertainties. Easy to spot new physics

M. Herndon One of the best indirect search channels at the Tevatron

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Bs(d) → μ+μ- Method

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Relative normalization search

Measure the rate of Bs(d) → μ+μ- decays

relative to B J/K+

Apply same sample selection criteria

Systematic uncertainties will cancel out in

the ratios of the normalization

Example: muon trigger efficiency same for

J/ or Bs s for a given pT

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BF(Bs → μ +μ−) =(Ncand − Nbg )

α BsεBs

•α

B +εB +

NB +

•fu

f s

•

BR(B+ → J /ψK +) • BR(J /ψ → μ +μ−)

400pb-1

9.8 X 107 B+ events

N(B+)=2225

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Discriminating Variables

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Mass M

CDF: 2.5σwindow: σ = 25MeV/c2

DØ: 2σwindow: σ = 90MeV/c2

CDF λ=cτ/cτBs, DØ Lxy/Lxy

α : |φB – φvtx| in 3D

Isolation: pTB/( trk + pTB

)

CDF, λ, α and Iso:

used in likelihood ratio

D0 additionally uses B and

impact parameters and vertex

probability

Unbiased optimization

Based on simulated signal and data

sidebands

4 primary discriminating variables

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CDF 1 Bs result: 3.010-6

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Bs(d) → μ+μ- Search Results

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CDF Result: 1(2) Bs(d) candidates observed

consistent with background expectation

Worlds Best Limits!

Decay

Total Expected Background

Observed

CDF Bs

1.27 ± 0.36 1

CDF Bd

2.45 ± 0.39 2

D0 Bs

0.8 ± 0.2 1.5 ± 0.3

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BF(Bs +- ) < 10.0x10-8 at 95% CL

BF(Bd +- ) < 3.0x10-8 at 95% CL

D0 Result: First 2fb-1 analysis!

BF(Bs +- ) < 9.3x10-8 at 95% CL

PRD 57, 3811 1998

Combined:

BF(Bs +- ) < 5.8x10-8 at 95% CL

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Bs → μ+μ-Physics Reach

Strongly limits specific SUSY models: SUSY SO(10) models

Allows for massive neutrino

Incorporates dark matter results

BF(Bs +- ) < 5.8x10-8 at 95% CL

Excluded at 95% CL

(CDF result only)

BF(Bs +- ) = 1.0x10-7

Dark matter constraints

L. Roszkowski et al. JHEP 0509 2005 029

A close shave for the

theorists

Typical example of SUSY Constraints

However, large amount of recent work

specifically on dark matter DSU 2007

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B Physics and Dark MatterB Physics constraints impact dark matter in two ways

Dark matter annihilation rates

Interesting for indirect detection experiments

Annihilation of neutralinos

Dark matter scattering cross sections

Interesting for direct detection experiments

Nucleon neutralino scattering cross sections

Models are (n,c)MSSM models with constraints to simplify the parameter space:

Key parameters are tanβ and MA as in the flavour sector along with m1/2

Two typical programs of analysis are performed

Calculation of a specific property: Nucleon neutralino scattering cross sections

Constraints from Bs(d) →μμ- and b s as well as g-2, lower bounds on the Higgs mass, precision

electroweak data, and the measured dark matter density.

General scan of allowed SUSY parameter space from which ranges of allowed

values can be extracted

M. Herndon Results can then be compared to experimental sensitivitiesDSU 2007

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SUSY and Dark Matter

M. Herndon Informs you about what types of dark matter Interactions are interesting

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2m ˜ χ ≈ mA

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m ˜ χ ≈ m ˜ τ

H. Baer et. al.

What’s consistent with the constraints?

There are various areas of SUSY

parameter space that are allowed by

flavour, precision electroweak and WMAP

Stau co-annihilation

Funnel

Bulk Region

Low m0 and m1/2, good for LHC

Focus Point

Large m0 neutralino becomes higgsino like

Enhanced Higgs exchange scattering diagrams

Disfavoured by g-2, but g-2 data is controversial

TeV

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Flavour Constraints on mNew analysis uses all available flavour constraints

Bs →μμ-, b s,Bs Oscillations, B

Later two results only 1 year old

CMSSM - constrained so that

SUSY scalers and the Higgs

and the gauginos have a

common mass at the GUT scale:

m0 and m1/2 respectively

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J. Ellis, S. Heinemeyer, K. Olive, A.M Weber and G. Weiglein hep-ph/0706.0652

Focus Point

Stau co-annihilation

Definite preferred

neutralino masses

~

This region favoured because of g-2

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Bs → μ+μ- and Dark MatterBs →μμ- correlated to dark matter searches

CMSSM supergravity model

Bs →μμ- and neutralino scattering cross sections are both a strong

functions of tanβ

In high tanβ(tanβ ~ 50), positive μ, CDM allowed

Current bounds on Bs →μμ- exclude parts of

the parameter space for direct dark matter detection

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More general scan in m0, m1/2 and A0, allowed region

S. Baek, D.G. Cerdeno Y.G. Kim, P. Ko, C. Munoz, JHEP 0506 017, 2005

CDF Paper Seminar 2007

R. Austri, R. Trotta, L. Roszkowski, hep-ph/0705.2012

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B Physics and Dark MatterPutting everything together including most recent theory work on b s

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R. Austri, R. Trotta, L. Roszkowski, hep-ph/0705.2012

Current experiments starting to probe interesting regions

Analysis shows a preference for the Focus Point

region, g-2 deweighted

Higgsino component of Neutralino is enhanced.

Enhances dominant Higgs exchange scattering

diagrams

Interesting relative to light Higgs searches at

Tevatron and LHC

Probability in some regions has gone down

However…

DSU 2007 S. Baek, et.al.JHEP 0506 017, 2005

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Current Xenon 10 ResultsLiquid Xenon detector

Multiple modules

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Xenon 10 Preliminary

R. Austri, R. Trotta, L. Roszkowski Current best limits

Excluding part of the high probability

region - 60 live day run!

Excluded by new Bs →μμ-

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Dark Matter ProspectsFrom dmtools.brown.edu

Just considering upgrades of

the two best current

experiments and LUX.

Prospects for dark matter

detection look good in CMSSM

models constrained by collider

data!

M. Herndon

Perhaps find both Dark

Matter and Bs → μ+μ-

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Excluded by new Bs →μμ-

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ConclusionsCollider experiments are providing a wealth of data on Flavour physics

as well as direct searches and precision electroweak data

These data can be used to constrain the masses and scattering cross

sections of dark matter candidates

Constrained MSSM models indicate that dark matter observation may

be within reach for current or next generation experiments! If Bs →μμ-

is there as well.

M. Herndon

A simulations observation of direct(or indirect) evidence

for new physics at a collider and Cold Dark Matter would

reveal much about the form of the new physics

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