Constraining CMSSM dark matter with direct detection results

Chris SavageOskar Klein Centre for Cosmoparticle Physics

Stockholm University

with Yashar Akrami, Pat Scott, Jan Conrad & Joakim EdsjöJCAP 1104:012, 2011 [arXiv:1011.4318]JCAP 1107:002,2011 [arXiv:1011.4297]

Overview

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Direct detection signalN, Ek=1..N , Sm, , , ...

WIMP parameters m , SI,p , SD,p , SD,n

Direct detection signalN, Ek=1..N , Sm, , , ...

CMSSM (e.g.) parameters m0, m1/2, A0, tanβ, sign(μ)

WIMP parameters m , SI,p , SD,p , SD,n

Phenomenology Particle (SUSY) TheoryMessy parameter space:

statistical scanning requiredWell behaved parameter space:

analytical methods for constraints?

Pheno space notfully mapped out

by CMSSM

This talkExperimental groupsJi-Haeng Huh talk

Overview

• How will future direct detection results constrain dark matter from supersymmetric theories?

Realistic reconstruction of dark matterproperties using CMSSM as case study

• Outline Basics: CMSSM, direct detection Analysis: likelihoods, statistics and scanning Phenomenological parameter constraints

• Individual/combined experimental results• Statistical/scanning issues• Halo model, hadronic uncertainties

CMSSM parameter constraints9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Basics andAnalysis Procedure

Basics

CMSSM (Constrained Minimal Supersymmetric Standard Model) Simplest SUSY model: four parameters + one sign Complicated parameter space: disconnected regions, sharp peaks,… Results/issues representative of generic SUSY models

(e.g. MSSM-7, BMSSM, NMSSM, etc.)

Direct detection:future ton-scale experiments XENON1T (Xe, neutron odd) [LUX, PANDA-X] CDMS1T (Ge, neutron odd) [EDELWEISS, CRESST?] COUPP1T (CF3I, proton odd)

Not included: CoGeNT, CDEX, DAMA, KIMS -like (higher backgrounds)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

DetectorWIMP

WIMPScatter

Analysis

Realistic analysis Typical thresholds and efficiencies Finite energy resolution Backgrounds at target levels (~ 2 events), known spectrum Uncertainties in halo model (density, velocity distribution) Hadronic uncertainties: WIMP-quark → WIMP-nucleon couplings

Likelihoods Direct detection

Nuisance parameters Halo model Nucleon structure SM parameters

…also physicality constraints9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

See paper for technical details

COUPP: no spectrum

Number of events (Poisson) Event energies (spectrum)

Analysis

Procedure Select CMSSM models that give particular m and SI,p :

benchmark models Generate random experimental results Reconstruct CMSSM model by scanning

over CMSSM parameter space• DarkSUSY + SuperBayeS (MultiNest)

Statistics Scan: Bayesian (SuperBayes) Results: Frequentist or Bayesian

• Profile likelihood (frequentist)• Marginalized PDF (Bayesian)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

www.darksusy.orgwww.superbayes.org

Most experimental analyses

Benchmark Models

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

BM1: low m , high SI,p O(100-400) signal events

BM2: low m , low SI,p O(1-3) signal events

BM3: moderate m and SI,p O(20-30) signal events

BM4: high m , high SI,p O(20-30) signal events

+ 2 background events (on average)

Benchmarks still below most recent XENON constraints

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Results(Constraints)

BM1: low m , high SI,p

Spin-independent/dependent cross-sections vs. mass XENON: ~ 200 signal events (~ 7 SD events)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

true value max likelihood posterior mean

BM1: low m , high SI,p

Spin-independent/dependent cross-sections vs. mass CDMS: ~ 140 signal events (~ 2 SD events)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

BM1: low m , high SI,p

Spin-independent/dependent cross-sections vs. mass COUPP: ~ 390 signal events (~ 120 SD events)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

BM1: low m , high SI,p

Spin-dependent couplings: neutron vs. proton an ≈ -ap : CMSSM prediction (not experimental constraint) O(5) [CDMS/XENON] vs. O(100) [COUPP] SD events

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

BM2: low m , low SI,p

Spin-independent/dependent cross-sections vs. mass ~ 1.4 / 2.1 / 3.0 signal events (~ 0 / 0 / 0.1 SD)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

BM3: moderate m and SI,p

Spin-independent/dependent cross-sections vs. mass ~ 17 / 23 / 32 signal events (~ 0 / 0 / 0.6 SD)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

BM4: high m , high SI,p

Spin-independent/dependent cross-sections vs. mass ~ 19 / 25 / 36 signal events (~ 0 / 0 / 0.3 SD)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Issues

Issue: sampling/coverage Mass constraint from energy spectrum:

degeneracy for heavy WIMPs

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Phenomenological parameter scanPato et al., PRD 83, 083505 (2011)

BM3

BM4

Issue: sampling/coverage

• Scan points without DD likelihood BM4 in poorly sampled region BM3 in higher sampled region

• Degeneracy: BM3 & BM4 should give

similar DD signals (N, Ei)

• BM4 scan: Good fit around BM3 Nothing to draw scan towards

BM4 region Too few models to properly

evaluate profile likelihood9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Issue: sampling/coverage

• Real priors and/or effective priors affect scan region

• Scan may miss some regions of interest or cover them too coarsely

• Can lead to significant over/under-coverage of confidence regions (frequentist) or credible regions (Bayesian)

• Possibly improved by higher statistics …if higher statistics gives sharper likelihood contours

(can overcome real/effective priors) Not for previous case

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Issue: nuisance parameters

• Halo model Local density, velocity distribution Standard Halo Model (SHM): isothermal sphere

• 3 velocity parameters: v0, vobs, vesc

Structure?• Annual modulation (DAMA, CoGeNT)• Directional detection (DRIFT)

• Hadronic matrix elements Used in calculating SI & SD from -quark couplings 6 relevant matrix elements (only 3 are important) Affect CMSSM constraints, not pheno constraints (at least not

directly)9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Halo models + direct detection:see Strigari & Trotta (2009)

and various works by A. Green

See Ellis, Olive & CS, PRD 77, 065026 (2008)

Halo model uncertainties

With / without uncertainties in halo model (nuisance parameters) Local DM density most significant

• See e.g. Strigari & Trotta, JCAP 11, 019 (2009)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

Hadronic uncertainties

With / without hadronic uncertainties (nuisance parameters) No change: affects only CMSSM parameter constraints

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

Hadronic uncertainties

With / without hadronic uncertainties (nuisance parameters) Only directly affects CMSSM parameter constraints

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

CMSSMConstraints

CMSSM constraints

No direct detection likelihood (priors and nuisance only)

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

CMSSM constraints (BM1)

With direct detection likelihood Gaugino mass (m1/2) best constrained (related to m) Weaker constraints on m0, A0, tanβ

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

Profile likelihood: ■ 1σ ■ 2σ

CMSSM constraints

• Can combine with other observational data: Indirect detection: cosmic-rays, neutrinos Accelerators Relic density, etc.

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection

-rays (Fermi-LAT)Segue 1 analysisScott et al. (2009)

Neutrinos (IceCube)IC collab + Edsjö, Scott, CS, in prep.

Accelerator (LHC: ATLAS)SU3 benchmark analysis

Bridges et al. (2010)

See Trotta et al., JHEP 0812:024 (2008)

Summary

• Examined realistic reconstruction of darkmatter properties in SUSY (e.g. CMSSM)theories using direct detection results

• Can reconstruct WIMP properties reasonablywell in some cases, not so well in others Coverage, sampling issues:

Accuracy affected by scanning technique Nuisance parameters

• Combine DD results with other observationsto better constrain SUSY theory parameters

9/27/2011 C Savage - DSU 2011 - CMSSM and Direct Detection