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Communication to thermal dark matter with large self-interactions - - PowerPoint PPT Presentation

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Communication to thermal dark matter with large self-interactions Hyun Min Lee (Chung-Ang University, Korea) Based on M.-S. Seo, Phys. Lett. B748, 316; S.-M. Choi, JHEP1509, 063 & To appear. GGI Workshop Gearing up for LHC13

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SLIDE 1

Communication to thermal dark matter with large self-interactions

Hyun Min Lee (Chung-Ang University, Korea)

GGI Workshop “Gearing up for LHC13” Florence, Italy, Oct 5, 2015

Based on M.-S. Seo, Phys. Lett. B748, 316; S.-M. Choi, JHEP1509, 063 & To appear.

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SLIDE 2

Outline

  • Motivation
  • SIMP DM from hidden QCD
  • SIMP DM from discrete symmetries
  • Conclusions
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SLIDE 3

Motivation

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SLIDE 4

Dark matter everywhere!

Large-scale evidences Galaxies (including our Milky Way)

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SLIDE 5

WIMP paradigm

  • WIMP DM density relies on 2→2 annihilation

processes with weak interactions.

DM DM SM SM

WIMP freeze-out:

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SLIDE 6

WIMP around the corner?

  • Direct/indirect/collider searches rule out a

wide range of WIMP dark matter.

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SLIDE 7

Non-WIMP?

  • WIMP paradigm is based mostly on the

assumption that DM is related to weak-scale physics solving the hierarchy problem.

  • But, dark matter might be

related to different problems such as QCD axion or some unknown hidden sector. more than this?

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SLIDE 8

DM self-interactions

  • Solve small-scale problems in galaxies: core-

cusp, too-big-to-fail, missing satellites, etc.

NFW overshoots data!

[D.H. Weinberg et al(2013)]

Bullet cluster & halo shape:

  • cf. WIMP DM:
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SLIDE 9

Abell 3827

  • Among four colliding galaxies observed by Hubble

Telescope, one of subhalo lags behind the galaxy.

DM subhalo separation

[Kahlhoefer etal (2015)] [Massey et al(2015)]

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SLIDE 10

SIMP paradigm

  • Strong Interacting Massive Particle(SIMP) is a

thermal DM, due to 3→2 self-annihilation.

DM DM DM DM DM

Freeze-out:

[Hochberg et al, 2014]

  • cf. WIMP:
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SLIDE 11

Large SIMP self-interaction

  • SIMP DM predicts typically large DM self-

interactions.

DM DM DM DM DM DM DM DM DM

Bullet cluster & spherical halo shapes.

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SLIDE 12

SIMP conditions

  • Equilibration of heat from

SIMP: kinetic equilibrium with SM bath.

DM SM DM SM

  • The same coupling leads to 2→2 DM

annihilation, which is subdominant when

time

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SLIDE 13

DM messengers

DM (X) SM (q)

“Messenger” A new force

DM SM DM SM

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SLIDE 14

SIMP DM from hidden QCD

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SLIDE 15

Hidden QCD with WZW term

  • Dark flavor symmetry G=SU(Nf)x SU(Nf) is

broken down to H=SU(Nf) by SU(Nc) QCD-like condensation.

  • Effective action for Goldstone bosons contains

a 5-point self-interaction from Wess-Zumino- Witten term for π5(G/H)=Z (i.e. Nf ≥3).

Flavor symmetry ensures stability of dark SIMP mesons.

NC : topological invariant

  • f 5-sphere (Q+Q’) in

SU(3) [Wess, Zumino,1971;Witten, 1983]

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SLIDE 16

SIMP dark mesons

  • “Large color group” leads to strong 5-point

interactions while satisfying bounds on self- interactions.

[Hochberg et al, 2014] ~const ~const

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SLIDE 17

[Hochberg, Kuflik, Murayama, Volansky, Wacker, 2014]

Bullet cluster, Halo shape

SIMP parameter space

Perturbativity

Self-scatt.

Perturbativity Bullet cluster

SIMP relic

Nc>3 is required due to bounds on self-scattering. Similar results for SU(Nf)/SO(Nf) or SU(2Nf)/Sp(2Nf).

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SLIDE 18

NLO corrections

  • 2→2: LO, 3→2: NLO

NLO corrections enhance 2→2 scattering cross sections, making the self-interaction bound stronger.

[Hansen et al, 2015]

Need a large color or large meson decay constant: additional annihilation channel ?

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SLIDE 19

Twin Higgs & mirror symmetry

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SLIDE 20

Mirror QCD

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SLIDE 21

SIMP mesons on orbifolds

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SLIDE 22

Dark mesons & Z’-portal

  • Dark meson can be in kinetic equilibrium with

the SM particles via Z’-Z kinetic mixing.

  • 2→2 annihilation with Z’-portal could be

suppressed (or be as large as 3→2 ann).

SM SM

  • cf. Higgs-portal coupling does not

work, because leptons in thermal bath have small Yukawa couplings.

3→2 dominance: SIMP conditions

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SLIDE 23

WZW with Z’

  • Modified WZW with U(1)’:

AVV anomalies. AAAV anomalies.

  • Dark quarks are vector-like under broken U(1)’.

Z’ Z’ Z’

[Witten, 1983]

DM decay 2→2 ann

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SLIDE 24

Stability of dark mesons

  • Stability of dark neutral mesons requires

the cancellation of AVV anomalies.

if

  • cf. QCD: Q=diag(2/3,-1/3,-1/3)

: flavor non-universal charges

Z’ Z’

±2 charges.

[HML, Seo, 2015]

  • π π→πZ’ is forbidden for mZ’ > mπ.
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SLIDE 25

Dark flavor violation

  • Flavor non-universal U(1) charges breaks

flavor symmetry leads to meson mass splitting:

  • Higher dimensional operators must be

suppressed by high cutoff or small coupling: DM stability:

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SLIDE 26

Z’ at colliders

  • SIMP conditions are complementary in

constraining Z’ parameters to direct Z’ searches.

SIMP conditions

SU(4) color SU(6) color

(BaBar), (CMS 8TeV), Drell-Yan, dileptons.

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SLIDE 27

SIMP DM from discrete symmetries

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Gauged Z3 and SIMP

  • 5-point SIMP interaction is inconsistent with

Z2 and flavor symmetry is broken.

  • Z3 is the minimal symmetry for stabilizing

SIMP, a remnant of a local U(1).

  • Built-in Z’ gauge boson communicates

with the SM via the kinetic mixing.

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SLIDE 29

A Z3 Model

  • : Dark Matter, : Dark Higgs, V: Dark photon.

[Belanger et al(2012); Ko, Tang(2014); S.M. Choi, HML, 2015]

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Scalar SIMP DM

  • 2→2 annihilation channels are forbidden

for heavy dark Higgs and Z’.

  • 3→2 annihilation channels are through

Higgs + Z’ exchanges:

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SLIDE 31

2→2 3→2

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SLIDE 32

Bounds on self-interaction

  • Bullet cluster & halo shape:
  • SIMP relic density:
  • Unitarity, perturbativity:

Abell 3827

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SLIDE 33

Kinetic equil. condition

  • SIMP conditions:

Higgs-portal: negligible for kinetic scatt., safe for Higgs (invisible) signals & indirect detections Z’-portal: works for kinetic scatt., bounded by collider searches, safe for indirect detections.

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SLIDE 34

SIMP & Z’ searches

  • SIMP conditions are complementary for

Z’ searches at colliders.

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SLIDE 35

Direct detection

  • SIMP dark matter scatters off electrons,

leading to small recoil energy:

Superconducting detectors? [Hochberg et al (2015)]

XENON10:

=

Blue ue:

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SLIDE 36

A Z5 model

  • 5-point interaction is picked up by Z5 ,

mediated by a heavy singlet scalar S (cf. no cubic coupling for DM).

[S.M.Choi, HML, to appear]

  • Z’ again makes SIMP DM in kinetic equilibrium.
  • Singlet scalar S can be stable too.
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SLIDE 37

Resonant 3→2 in Z5

  • 5-point interaction in Z5 can be

enhanced near resonance.

safe from the bounds from self-interactions (with potentially large NLO).

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SLIDE 38

Phase diagram of DM

(semi-)annihilation

WIMP phases need a sizable annihilation into the SM, e.g. Z’ portal.

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SLIDE 39

Conclusions

  • SIMP paradigm leads to testable scenarios

via DM self-interactions as well as possibly, messengers particles.

  • SIMP dark mesons can be in kinetic

equilibrium with Z’ portal and remain stable.

  • Scalar SIMP dark matter with discrete gauge

symmetries has a built-in Z’-portal.

  • For discrete symmetries of high degree, we

need a scalar mediator for 5-point interactions, which can be enhanced near resonance.