WIMP暗黒物質探査の現状と将来
Shigeki Matsumoto (Kavli IPMU)
Collaborators: Members in IPMU WIMP PROJECT
S. M., S. Mukhopadhyay, Y. L. Sming Tsai, [JHEP 1410 (2014) 155]
S. Banerjee, S. M., K. Mukaida, Y. L. Sming Tsai, [arXiv:1603.07387]
S. M., S. Mukhopadhyay, Y. L. Sming Tsai, [arXiv:1604.02230]

What is the current status of the WIMP paradigm?
How far can we cover the WIMP paradigm in future?
What is the leftover remaining as unexplored regions?

Purpose of the project is to answer these questionswithout relying on any specific new physics models.

1/15

WIMP hypothesis
Particle dark matter

GeV
10 –28

10 50

1/15

WIMP hypothesis
Particle dark matter

GeV
10 50

10 –28WIMP hypothesis
Dark matter is a electromagnetically neutral and stable particle with themass of roughly 100GeV, and it has a usual coupling to SM particles.

1/15

WIMP hypothesis
Particle dark matter

GeV
10 50

10 –28WIMP hypothesis
Dark matter is a electromagnetically neutral and stable particle with themass of roughly 100GeV, and it has a usual coupling to SM particles.

WIMP dark matter
GeV
10 5

10 –3

Well-motivated region!
(close to EWSB scale)2/15

WIMP hypothesis
WIMP hypothesis

Dark matter is a electromagnetically neutral and stable particle with themass of roughly 100GeV, and it has a usual coupling to SM particles.
 Neutrality … By definition.
Stability … By definition. (There must be some symmetry behind it.)Coldness … WIMP decouples from thermal bath when non-relativistic.
 Abundance … It is predicted to be WDM h2 ～ 0.1 (1pb/<sv>)2.  FTFT!

Why is WIMP attractive?
Theoretically, the mass of WIMP andthe origin of EWSB can be the same!
Experimentally, there exists a lot ofopportunities to detect WIMP, since
the coupling between WIMP and SM
particles are not suppressed.

Quarks,SMLeptons,↓Is there some framework to discuss
WIMP detections systematically w/odepending on any specific BSM?

WIMP

Higgs,W/Z

Covering WIMP Theory Space by the Patches

3/15

Once the spin of WIMP is fixed, the WIMP field can always be written
as a linear combination of colorless representations of the SM gaugegroup, viz. SU(2)L×U(1)Y, which must involve EM neutral components:

1034½,27…

Covering WIMP Theory Space by the Patches

3/15

Once the spin of WIMP is fixed, the WIMP field can always be written
as a linear combination of colorless representations of the SM gauge
group, viz. SU(2)L×U(1)Y, which must involve EM neutral components:

1034½,
27…

Singlet-like Patche.g.
Bino-like in SUSYKK photon in UED

Covering WIMP Theory Space by the Patches

3/15

Once the spin of WIMP is fixed, the WIMP field can always be written
as a linear combination of colorless representations of the SM gauge
group, viz. SU(2)L×U(1)Y, which must involve EM neutral components:
Doublet-like Patche.g.

10

Higgsino-like in SUSY
Inert Higgs in 2HDM

34½,
27…

Singlet-like Patche.g.
Bino-like in SUSYKK photon in UED

Triplet-like Patche.g.
Wino-like in SUSY
Quintet-like Patche.g.
Minimal dark matterCovering WIMP Theory Space by the Patches

3/15Once the spin of WIMP is fixed, the WIMP field can always be written
as a linear combination of colorless representations of the SM gauge
group, viz. SU(2)L×U(1)Y, which must involve EM neutral components:
Singlet-like Patche.g.
Bino-like in SUSYKK photon in UED

Higgsino-like in SUSY
Inert Higgs in 2HDM

4½,
3

S-D Mixed Patche.g.
Bino-Higgsino WIMP

27…

D-T mixed Patche.g.
Higgsino-wino WIMP

Doublet-like Patch
e.g.

10

Triplet-like Patche.g.
Wino-like in SUSY
Quintet-like Patche.g.
Minimal dark matterBasic strategy

4/15

1. Constructing the effective Lagrangian in each patch, with particle
contents as minimal as possible. It should include all interactions
that can be responsible for the relic abundance calculation.
2. Considering various constraints from WIMP searches as well as
the relic abundance limit to figure out viable parameter space.
WIMP search results

Relic abundance limit

Giving upper limits on
the WIMP interactions.

Giving lower limits on
the WIMP interactions.

These opposite requirements make the WIMP parameter space finite!

In this talk, we will focus on a fermionic WIMPin the S-D mixed & the Singlet-like patches!
light WIMPs!

Constraints on the WIMP parameter space

5/15

DM relic abundance limit
Putting a (lower) limit on dark matterinclusive annihilation cross section.
WWIMP h2 = 0.12 (WWIMP h2 ≦ 0.12)

The dark matter abundance today is
assumed to be determined by thermal(+ a non-thermal) production.
Direct DM detection constraints
Putting upper limits on the scatteringcross section between DM and nucleon.
Present status:
LUX for SI/SDn and PICO-60 for SDp
Future prospects:
LZ for SI/SDn and PICO250 for SDp(assuming no signals detected.)

Constraints on the WIMP parameter space

6/15

Indirect DM detection constraints
Putting an upper limit on dark matter(semi-inclusive) annihilation X-section.
PLANCK (DM ann. @ recombination era)
Other indirect detections have yetlarge systematic uncertainties.
Constraints from collider experiments
Putting upper limits on the production
cross section of the DM particle.
Invisible Z decay (LEP), Mono-jet (LHC)
Invisible H decay (LHC/ILC),
Mono-g (LEP/ILC), Others (LHC)(electroweakino, multi-jets, etc.)
All these constraints are taken into account in the likelihood analysis
based on the Markov Chain Monte Carlo (MultiNest Sampling) method.

WIMP in the S-D mixed patch

7/15

Minimal contents: 10, 2½, 2–½ (Anomaly cancel.)Patch coverage: |zS|2 < 0.95 & |zD|2 < 0.95
✔ Effective lagrangian for the contents is(Z2 symmetry is assumed to make WIMP stable.)✔ Model parameters are(3 neutral Majorana + 1 charged Dirac)

MS : Singlet mass parameter (Corresponding to M1in MSSM)
MD : Doublet mass parameter (〃to min 〃 )y1 =ycosq : U-type Yukawa coupling (〃to ycosb in 〃 )y2 =ysin q : D-type Yukawa coupling (〃to ysin b in 〃 )with y being y = g’/2½✔ Model parameter space is

CP invariance is assumed. y ≦ 1 is also assumed in our analysis!

Present status in the S-D mixed patch

8/15

Present status(The likelihood function is now projected onto the (MDM, MD)-plane.)Resonance regions

Coannihilation region

Present status in the S-D mixed patch

8/15

H-blind spot region

Present status(The likelihood function is now projected onto the (MDM, MD)-plane.)Future prospects in the S-D mixed patch

9/15

Present status(The likelihood function is now projected onto the (MDM, MD)-plane.)Future prospects in the S-D mixed patch

9/15

After XENON1T(The likelihood function is now projected onto the (MDM, MD)-plane.)Future prospects in the S-D mixed patch

9/15

After LZ/PICO250(The likelihood function is now projected onto the (MDM, MD)-plane.)Future prospects in the S-D mixed patch

10/15

Only coannihilation regions survives after O(1)ton level experiments!
When Rs is suppressed, indirect DM detections will be very important.
(Controlling systematic errors of the experiments will be mandatory.)
When Rs is not suppressed, future e+e– colliders will be very important.
(To cover entire region, TeV-scale lepton colliders will be mandatory.)WIMP in the Singlet-like patch

11/15

Minimal content: 10 (One Majorana fermion)Singlet WIMP cannot interact with SM particles
by alone because of the Z2 symmetry making theWIMP stable, so that some other new particles
must be introduced. Assuming those are heavy
enough, we introduce higher dim. operators.
Small mixing effects are automatically involved i.
Patch coverage: 1 – O(v2/L2) < |zS|2 < 1(v is the VEV of Higgs field.)✔ Effective lagrangian for the content is✔ Many model parameters, so that we impose simplifying assumptions:

・ Common suppression scale (Li = L) with L > [3 mDM, 300 GeV].
・ All coupling constants ci are smaller than one.
・ Flavor blindness ([cf]ij = cf) and CP invariance (cP = 0).

WIMP in the Singlet-like patch

12/15

The EFT description is of limited applicability to discuss WIMP signals
at energetic colliders, so that we consider a general simplified model
which reproduces the EFT at large intermediate particle mass limits.

12/15WIMP in the Singlet-like patch

The EFT description is of limited applicability to discuss WIMP signals
at energetic colliders, so that we consider a general simplified model
which reproduces the EFT at large intermediate particle mass limits.

Hc
Scalar fPfc

H
Vector VH

Vector Vf

Hc

H

c

fc

H

Hc

Hcfc

H

Hc

Hc

fc

Fermion yHcc

Scaler ff
Vector Vfcc

Fermion yS

Scalar fS

HFermion yPc

H12/15WIMP in the Singlet-like patch

The EFT description is of limited applicability to discuss WIMP signals
at energetic colliders, so that we consider a general simplified model
which reproduces the EFT at large intermediate particle mass limits.

Using these simplified models to take collider constraints into account!

Scalar fP+c

H

Vector Vf+cf

H
Vector VH+c

H

cfc

H

Hc

Hcfc

H+
Hc+
Hc+
fc

Fermion yH

HScaler ff
Vector Vfc

Fermion yS

Scalar fSccc

HFermion yPcH

Present status in the Singlet-like patch

13/15

Present status(The likelihood function is now projected onto the (MDM, Λ)-plane.)H resonance regions

4-Fermi region

Z resonance regions

H resonance regions

Z resonance regions

Present status in the Singlet-like patch

13/15

4-Fermi region

Present status(The likelihood function is now projected onto the (MDM, Λ)-plane.)Future prospects in the Singlet-like patch

14/15

Present status(The likelihood function is now projected onto the (MDM, Λ)-plane.)Future prospects in the Singlet-like patch

14/15

After XENON1T(The likelihood function is now projected onto the (MDM, Λ)-plane.)Future prospects in the Singlet-like patch

14/15

After LZ/PICO250(The likelihood function is now projected onto the (MDM, Λ)-plane.)Future prospects in the Singlet-like patch

14/15

O(10)ton level direct detection cover the H resonance region entirely.
The Z resonance region will be widely covered by SD direct detections.
(Remaining part could be covered by luminous lepton colliders, Giga-Z.)
The 4-Fermi region has already been restricted to be below Λ<10mDM.
(Hadron and Lepton colliders can efficiently cover the remaining part.)

H resonance regions

Future prospects in the Singlet-like patch

14/15

O(10)ton level direct detection cover the H resonance region entirely.
The Z resonance region will be widely covered by SD direct detections.
(Remaining part could be covered by luminous lepton colliders, Giga-Z.)
The 4-Fermi region has already been restricted to be below Λ<10mDM.
(Hadron and Lepton colliders can efficiently cover the remaining part.)Summary

15/15

 The era of serious WIMP searches has begun!

What is the current status of the WIMP paradigm?
How far can we cover the WIMP paradigm in future?
What is the leftover remaining as unexplored regions?
We have proposed a framework in order to answer these questions
without relying on any specific new physics models beyond the SM.

 Direct dark matter detections & LHC are playing important roles!
We have focused on a fermionic WIMPs in
the S-D mixed & the Singlet-like patches.
・ In the S-D mixed patch, the coannihilation
region remains after LZ & LHC experiments.
・ In the single-like patch, the Z resonance &4-Fermi (lepton) regions remains after LZ& LHC when a mediator particle is heavy.
・ Further studies are needed for the singletlike WIMP with a light mediator particle.
 Experiment probing other WIMP interactions (ILC) will be important.

Backup (Constraints from LHC)
We use LUV+ & LUV– instead of LEFT to evaluate constraints from colliers.
✔ Invisible Higgs decay @ LHC: Sensitive to the scalar type coupling.
✔ Invisible Z decay @ LEP: Sensitive to WIMP-Higgs current coupling.
✔ Mono-g search @ LEP: Sensitive to WIMP-Lepton & Higgs couplings.
✔ Mono-jet search @ LHC: Sensitive to WIMP-Quark couplings.
Decay widths of mediator particles are fixed as G=L/2 in the analysis.

Are there some other channels?
 Radiative corrections (off-shell contributions) from the mediators.
Mediator particles may contribute to some SM processes (e.g. SM
4-Fermi couplings). The contribution could be, however, alleviatedby introducing other new particles coupled only to SM particles.
 On-shell productions of the mediator particles at the LHC.
Some single productions (and decays into WIMP) are included.
For Z2-even mediators, single productions into 2jets are weaker.
For Z2-odd mediators, pair productions give weaker signals.