• No results found

Thoughts on Neutralino Dark Matter

N/A
N/A
Protected

Academic year: 2022

Share "Thoughts on Neutralino Dark Matter"

Copied!
34
0
0

Loading.... (view fulltext now)

Full text

(1)

Thoughts on Neutralino Dark Matter

Pearl Sandick

University of Utah

(2)

Old Results in Dark Matter

• Galactic Rotation Curves

• Cluster Dynamics (incl. collisions)

• Velocity dispersions of galaxies - dark matter extends beyond the visible matter

• Weak Gravitational Lensing (distribution of dark matter)

• CMB (+ Type 1A SNe, plus BAO) all agree on LambdaCDM

• Structure Formation

• Some explanation is necessary for observed gravitational phenomena.

• It’s largely non-relativistic (cold).

• Its abundance is ΩDM≈0.26.

• It’s stable or very long-lived.

• It’s non-baryonic (BBN+CMB, structure).

• It’s neutral (heavy isotope abundances).

Observations Summary

(3)

Current Situation

• Abundance of experimental data!

‣ We’re exploring dark matter with unprecedented and

growing precision - both experimentally and theoretically.

• Theoretical approaches:

Totally Data-Driven

Totally Theory-Driven

(4)

Current Situation

• Abundance of experimental data!

‣ We’re exploring dark matter with unprecedented and

growing precision - both experimentally and theoretically.

• Theoretical approaches:

Totally Data-Driven

Totally Theory-Driven

Hybrid / Simplified Models

(5)

Effective Theories

(McCabe talk on Monday)

• Idea: Reduce DM-SM interaction to a contact interaction.

• Universe of possible interactions is small (can enumerate)

• Utility in evaluating

complementarity of detection techniques (good)

• Range of validity (careful)

DM

DM

SM

SM

New Physics

Collider Searches Indirect Detection

Di rect Detecti on

Relic Abundance

(6)

Fundamental Theory

Supersymmetry

MSSM Non-Minimal Model

mSUGRA

CMSSM

NUHM

Gravity Mediation Gauge Mediation EW-Scale Inputs

pMSSM

MSSMn (n=7,9,etc.)

Relevant Parameters Only

(7)

SUSY Dark Matter

1. What is predicted within the SUSY framework?

‣ specific realization or more general possibilities 2. What are the data really telling us?

‣ Priors on model ➔ different interpretations 3. When will we know for sure?

‣ Direct Dark Matter Searches

(8)

Dimensionality

25-D

!

!

19-D

!

!

{m 1/2 , m 0 , A 0 , tan 𝜷, sign(μ)}

6-D

!

!

5-D

!

!

4-D

!

!

3-D 2-D !

CMSSM

Polonyi mSUGRA

➡ {m 1/2 , m 0 , sign(μ)}

mSUGRA NUHM1 NUHM2

{m 1/2 , m 0 , A 0 , sign(μ)}

pMSSM

MSSM25

(9)

Polonyi mSUGRA

m h = 122.

5 G eV m h =

119 G eV

m h = 124 GeV

𝛘 -LSP

G-LSP

~

~ chargino

mass bound

Ω 𝛘 > Ω CDM

LHC bound

m h =

114 G eV

Ellis, Luo, Olive, Sandick (2013)

Increase

dimensionality?

(10)

Universality Scale

• Input universality scale, M in , assumed to be M GUT

• Could be larger: “superGUT”

• SUSY breaking and mediation characterized by Planck or string scale

!

• Could be smaller: “subGUT/GUTless”, “Mirage”, or “TGM”

!

• Lowest dynamical scale in the Polonyi/hidden sector where SUSY is broken, or scale of interactions that transmit breaking to observable sector

Polonsky & Pomarol (1994)

For recent analyses, see Ellis, Mustafayev, & Olive (2010,2011)

Choi et al. (2004, 2005), Kachru et al. (2003),

and others Ellis, Olive, & Sandick

(2006, 2007, 2008);

Ellis, Luo, Olive,

& Sandick (2013)

Monaco et al.

(2011)

(11)

Dark Matter Abundance

No EW SB

(m 1/2 , m 0 ) = (1.5 TeV, 1.5 TeV)

!

1. neutralino LSP

becomes Higgsino-like at low M in

!

2. m A decreases with M in

→ appearance of rapid annihilation funnel

(2-loop results)

Hi ggs ino (μ )

bino (M 1 ) M A /2 neutra

lino

(12)

sub-GUT mSUGRA

Ω𝛘 la rge Ω𝛘 la rg e

Ω𝛘 sma ll

Ω𝛘 sma ll

Ellis, Luo, Olive,

Sandick (2013)

(13)

To Higher Dimensions…

• There are still viable, few-parameter models motivated by high-scale physics.

• Strength: one of these models might actually describe our Universe!

• Strength: understand how observables change in the parameter space!

• Weakness: may be missing important model classes

• Higher dimensional models more fully explore the possible

combinations of observables (if sampling of the model space

is adequate!).

(14)

pMSSM

Cahill-Rowley et al. (2013)

(15)

3. When will we

know for sure?

(16)

Future Prospects

• Timeline for discovery/exclusion?

Akerib et al. (LUX Collaboration), 2013

?

Simplified models can help you

construct a definite, model-independent

answer.

Could answer within a low-dimensional model (not general),

or within the MSSM

(not conclusive).

(17)

Resonance Models

• Neutralino:

!

• s-channel resonance annihilations occur when

• As increases, decreases

• If too large, increase Higgsino content:

• Scattering with quarks is governed by

!

• Relevant parameters:

0 1

~

0

1

~

N

11

N

11

0 1

~

0

1

~

~

q q

q

q

q q

N

13

h , H

(18)

If DM abundance is achieved through a resonance, how small could σ SI possibly be?

Hooper, Kelso, Sandick, & Xue, PRD 2013

all detectable on

~decade timescale

• Relic Abundance: μ

• Higgs mass: A 0

• Free parameters:

(m 0 , M 1 , m A , tanβ)

A

0

/m

0

A

0

/m

0

μ (TeV) μ (TeV)

Ω

χ

h

2

m

h

(19)

If DM abundance is achieved through a resonance, how small could σ SI possibly be?

Hooper, Kelso, Sandick, & Xue, PRD 2013

all detectable on

~decade timescale

If Nature is MSSM-like, and neutralino dark matter at a resonance makes up all

the dark matter in the Universe, then direct detection experiments are pushing the resonance to be more and more exact.

At this rate of progress, direct detection experiments will be able to close the A/H/h funnel

regions in just over a decade!

• Relic Abundance: μ

• Higgs mass: A 0

• Free parameters:

(m 0 , M 1 , m A , tanβ)

(20)

Data-Driven SUSY

• 2. What are the data telling us?

‣ Investigate parameter space near current constraints.

‣ Dramatically different answers, depending on assumptions!

• What we really know about sparticles: sleptons, charginos, and 3rd gen. squarks heavier than ~100 GeV, 1st/2nd gen. squarks heavier than ~1.1 TeV, gluino heavier than ~1 TeV

• Other constraints: Higgs ~126 GeV, dark matter, rare B decays, electric dipole moments, anomalous magnetic moments

• Simple model: bino-like LSP and light sleptons (everything else heavy)

Fukushima, Kelso, Kumar,

Sandick, & Yamamoto (in prep.)

(21)

Light Sleptons

• Relic Abundance:

• Dipole Moments:

(22)

Light Smuons Scenario (M 1 ≠M 2 )

Fukushima, Kelso, Kumar, Sandick, & Yamamoto (in prep.)

(23)

Light Sleptons

• Annihilation Cross Section:

• Dipole Moments:

maximal when α=nπ/4, n odd

zero when

α=nπ/2, n integer

or M 1 =M 2

(24)

Light Smuons Scenario (M 1 ≠M 2 )

Fukushima, Kelso, Kumar, Sandick, & Yamamoto (in prep.)

(25)

Light Smuons Scenario (M 1 ≠M 2 )

(26)

Light Smuons Scenario

(27)

Light Sleptons (M 1 ≠M 2 )

Fukushima, Kelso, Kumar, Sandick, & Yamamoto (in prep.)

0

p2

p

3 p

2

2 p

0

p 4 p 2 3 p 4

p

j

a

0

p2

p

3 p

2

2 p

0

p 4 p 2 3 p 4

p

j

a

0

p2

p

3 p

2

2 p

0

p 4 p 2 3 p 4

p

j

a

Light μ ~ Light 𝛕~

Light e~

If M

1

=M

2

, dipole moments vanish, but too much dark matter.

• Light e: Angles must be tuned to α ≲10

-3

and φ ≲10 -6 , but relic abundance is too large

Light μ: Possible to obey dipole moment constraints (or explain Δa), and have thermal dark matter (for small range of φ)

Light 𝛕: Relic abundance is the only constraint (see also Pierce, et al.; Hagiwara et al., 2013)

~

~

~

(28)

Other Signatures

• Indirect Detection:

• Best Case Scenario is annihilation to taus. Possibly within reach of Fermi (dSphs).

• Annihilation to neutrinos:

Unconstrained by dipole moments, but annihilation rate is small (relic abundance too large). Probably not detectable at IceCube or SK.

• CMB: not currently constrained for

annihilations to muons or taus, and will remain just out of reach, even for CVL experiment

7

100 101 102 103 104

Mc [GeV]

10 28 10 27 10 26 10 25 10 24 10 23 10 22

feffhsvi[cm3 s1 ]

WMAP9

Current (WMAP9+Planck+ACT+SPT+BAO+HST+SN) Full Planck temp. and pol. forecast

CMB Stage 4 forecast Cosmic Variance Limit WMAP9

Current (WMAP9+Planck+ACT+SPT+BAO+HST+SN) Full Planck temp. and pol. forecast

CMB Stage 4 forecast Cosmic Variance Limit

FIG. 5: From top to bottom — constraints on pann from WMAP9 alone (pink) and from current data including WMAP9, Planck TT power spectrum and 4-point lensing signal, ACT, SPT, BAO, HST, and SN data (blue). Also shown are Fisher forecasts for the complete Planck temperature and polarization power spectra (green), for a proposed CMB Stage IV experiment (purple), and for a cosmic variance limited experiment (up to l = 4000) (red). The dashed line shows the thermal cross section of 3⇥ 10 26cm3s 1 for fe↵ = 1. The dot-dashed line shows the thermal cross section multiplied by a typical energy deposition fraction of fe↵ = 0.2 (see Table III).

matrix approach, di↵erences between the data and the idealized ⇤CDM baseline used for the Fisher analysis, the e↵ect of including non-CMB datasets, and the few- percent uncertainty in the constraints due simply to scat- ter between CosmoMC runs.

The greatest improvement to the WMAP9-only con- straint comes from adding the Planck TT spectrum (⇠ 50%) as it particularly constrains the spectral index ns which is strongly degenerate with the annihilation pa- rameter pann (see Figure 4). The high-l CMB and BAO datasets improve our constraints by 8% and 9%, respec- tively. Adding to this the HST and Supernova data do not considerably improve these limits.

IV. DISCUSSION

The constraint obtained from using the updated universal deposition curve and including all avail- able datasets is a factor of ⇠ 2 stronger than that from WMAP9 data alone [25]. The strongest con- straint, including all available data, of pann < 0.66 ⇥ 10 6m3s 1kg 1 at 95% CL, excludes annihilating dark matter of masses M < 26 GeV, assuming a thermal cross section of 3⇥ 10 26cm3s 1 and perfect absorption of injected energy (fe↵ = 1). Using a more realistic ab- sorption efficiency of fe↵ = 0.2, we exclude annihilating

thermal dark matter of masses M < 5 GeV at the 2 level.2

These constraints can be compared to dark matter models explaining a number of recent anomalous results from other indirect and direct dark matter searches. Re- cent measurements by the AMS-02 collaboration [33]

confirm a rise in the cosmic ray positron fraction at en- ergies above 10 GeV, which was found earlier by the PAMELA [34] and Fermi collaborations [35]. Such a rise is not easy to reconcile with known astrophysical pro- cesses, although contributions from Milky Way pulsars within ⇠ 1 kpc of the Earth could provide a possible ex- planation [36–40]. Dark matter annihilating within the galactic halo also remains a possible explanation of the positron excess [41–44]. Dark matter models considered in [42] to explain the AMS-02/PAMELA positron excess cannot have significant annihilation into Standard Model gauge bosons or quarks in order to be consistent with the antiproton-to-proton ratio measured by PAMELA, which is found to agree with expectations from known astrophysical sources [45]. In addition, the combination of the Fermi electron plus positron fraction [46, 47] and

2 This constraint on pannis a factor of two weaker than that found by [9], possibly due to the priors chosen in that work.

Madhavacharil et al. (2013)

10

22

10

23

10

24

10

25

10

26

h vi (cm

3

s

1

)

e+e

Observed Limit Median Expected 68% Containment 95% Containment

10

22

10

23

10

24

10

25

10

26

h vi (cm

3

s

1

)

µ+µ

10

1

10

2

10

3

Mass (GeV/c

2

) 10

22

10

23

10

24

10

25

10

26

h vi (cm

3

s

1

)

+

FIG. 5. Constraints on the dark matter annihilation cross section at 95% CL derived from a combined analysis of 15 dwarf spheroidal galaxies assuming an NFW dark matter distribution (solid line). In each panel bands represent the expected sensitivity as calculated by repeating the combined analysis on 300 randomly-selected sets of blank fields at high Galactic latitudes in the LAT data. The dashed line shows the median expected sensitivity while the bands represent the 68% and 95% quantiles. For each set of random locations, nominal J-factors are randomized in accord with their measurement uncertainties. Thus, the positions and widths of the expected sensitivity bands reflect the range of statistical fluctuations expected both from the LAT data and from the stellar kinematics of the dwarf galaxies. The most significant excess in the observed limits occurs for the b¯b channel between 10 GeV and 25 GeV with TS = 8.7 (global p-value of p ⇡ 0.08).

36

Ackermann et al. (2014)

(29)

Light Sleptons (M 1 ≠M 2 )

Fukushima, Kelso, Kumar, Sandick, & Yamamoto (in prep.)

0

p2

p

3 p

2

2 p

0

p 4 p 2 3 p 4

p

j

a

0

p2

p

3 p

2

2 p

0

p 4 p 2 3 p 4

p

j

a

0

p2

p

3 p

2

2 p

0

p 4 p 2 3 p 4

p

j

a

Light μ ~ Light 𝛕~

Light e~

If M

1

=M

2

, dipole moments vanish, but too much dark matter.

• Light e: Angles must be tuned to α ≲10

-3

and φ ≲10 -6 , but relic abundance is too large

Light μ: Possible to obey dipole moment constraints (or explain Δa), and have thermal dark matter (for small range of φ)

Light 𝛕: Relic abundance is the only constraint (see also Pierce, et al.; Hagiwara et al., 2013)

~

~

~

Viable scena rios with bino-like

dark matter and light smuons/s taus.

(30)

Summary

• Finite distinct ways to observe dark matter:

• Abundance, Annihilation Today, Decay Today, Production at Colliders, Direct Detection

• A spectrum of theoretical approaches to particle dark matter

pot o f go ld

ahea d

(31)

Extra Slides

(32)

Looking Forward

• Direct dark matter searches - towards the neutrino background! and directional searches!

• Indirect dark matter searches

• Fermi, HAWK, VERITAS, AMS-02, GAPS, CTA GAMMA-400…

• LHC - SUSY/DM discovery potential at 14 TeV

• 100 TeV Hadron Collider

• Linear Collider - ILC at 500 GeV, CLIC at 3TeV

(33)

sub-GUT mSUGRA

Ω𝛘 la rge Ω𝛘 la rg e

Ω𝛘 sma ll

Ω𝛘 sma ll

Ellis, Luo, Olive,

Sandick (2013)

(34)

sub-GUT mSUGRA

At large tan 𝜷,

0 0

1 2

100 150

50

95% CL

large enough: m H ≈126 GeV

small enough: BR(B s →µ + µ - )≲1.5 SM value

A 0 {

Polonyi Model

seems to be

the sweet spot!

References

Related documents

● A different perspective on DM clustering (in phase space) using the Particle Phase Space Average Density (P 2 SAD)?. ● DM annihilation can be computed directly from the P 2 SAD

Motivation: relevance of EW corrections in modeling the predicted DM fluxes Current literature:. specific models corresponding to some MSSM neutralino

Direct and indirect detection rates have been computed implementing two dark matter halos, with fully consistent density profiles and velocity distribution functions, and

As one of the important features of the VLTC model, after the chiral symmetry breaking in the T-quark sector the left and right components of the original Dirac T-quark fields

• Indirect detection of particles produced in dark matter annihilation: neutrinos, gamma rays &amp; other e.m!. waves, antiprotons, antideuterons, positrons in ground-

Abbasi et al., Limits on a muon flux from Kaluza–Klein dark matter annihilations in the Sun from the IceCube 22-string

Chapter 7 presents analysis details and results for a search for muon neutrinos from dark matter annihilation in the center of the Sun using the 79-string configuration of the

6.4.4 Stellar velocity anisotropy effects on h vi upper limits 79 7 J-factors for self-interacting Dark Matter models 81 7.1 Generalised