Multiparticle Dark Matter and implications for detection Purusottam - - PowerPoint PPT Presentation

Multiparticle Dark Matter and implications for detection

Purusottam Ghosh IIT Guwahati, India YSF, Moriond EW 2019, La Thuile, Italy based on

JHEP 1902 (2019) 059, S. Bhattacharya, P.Ghosh and N.Sahu [arXiv: 1809.07474]

Purusottam Ghosh IIT Guwahati March 21, 2019 1 / 10

Dark Matter

Rotation Curve of Galaxies

• 0.1133  ⌦h2  0.1189
• CMB data
• Properties of DM particles:

EM charge neutral Weakly-interacting Still around today (stable) Massive (cold/non-relativistic) Weeakly Interacting Massive Particle (WIMP)

• None of the SM be the suitable

candidate of Dark Matter.

• What kind of elementary

particles can be Dark Matter ? ⇒ We do not know. φDM = {ψdark

Fermion, Aµdark Boson, φdark Scalar, .....}

(dark ≡ EM charge neutral) Purusottam Ghosh IIT Guwahati March 21, 2019 2 / 10

The Model

• SM Extension: A scalar singlet (S) and three vectorlike fermions:

two singlets (χ1, χ2) and a doublet,N = (N0 N−)T .

Dark Fields SU(3)C × SU(2)L × U(1)Y

• ×Z2 × Z′2

N =

• ( N0

N−

• 1

2

• 1
• +

χ1 1 1

• +

χ2 1 1 +

• S

1 1

• L

⊃ LV LF + LScalar + Lmessenger. Lmessenger = χ2 (iγµ∂µ − mχ2) χ2 −Y2(χ1χ2S + h.c).

• χ2 behave as a messenger

between scalar and VF DM sector.

Purusottam Ghosh IIT Guwahati March 21, 2019 3 / 10

Single component DM scenarions Scalar DM and Vectorlike fermionic DM

• Scalar DM : A real singlet, S .

Z2 : S → −S .

LScalar = 1 2 ∂µS∂µS − 1 2 m2

SS2

− 1 4! λSS4 − 1 2 λSH

• H†H −

v2 2

• S2

ref: V. Silveira and A. Zee

• Parameters: {mS, λSH}

Purusottam Ghosh IIT Guwahati March 21, 2019 4 / 10

Single component DM scenarions Scalar DM and Vectorlike fermionic DM

• Scalar DM : A real singlet, S .

Z2 : S → −S .

LScalar = 1 2 ∂µS∂µS − 1 2 m2

SS2

− 1 4! λSS4 − 1 2 λSH

• H†H −

v2 2

• S2

ref: V. Silveira and A. Zee

• Parameters: {mS, λSH}
• Fermionic DM : Admixture of

vector-like fermionic singlet (χ1) and a doublet (N) .ref: PRD93(2016)no.11,

115040 LV LF = N [iγµ(∂µ−ig σa 2 W a

µ − ig′ Y ′

2 Bµ) − mN ] N +χ1 (iγµ∂µ − mχ1 ) χ1−(Y1N Hχ1 + h.c)

• {N0, χ1} → {N1, N2} (Physical States) The lightest

physical states N1 (mN1 < mN2 ) be a stable DM .

• Parameters: {mN1 , ∆m(= mN2 (mN± ) − mN1 ), sin θ}

Purusottam Ghosh IIT Guwahati March 21, 2019 4 / 10

Multi-Component DM model

• Non observations of direct search put strong constarints on single component DM parameter

space.

• ∆m = mN± − mN1 12 GeV, Vector like fermionic DM can not observe at LHC due to

dominate SM background.

• In presence of an interacting two component framework, the

situation alters.

• Yukawa Interaction: Y2χ1χ2S

Type-I : mχ2 > mN1 + mS : Stable DM components:

• 1. Vector like Fermion , N1 ,
• 2. Real Scalar Singlet , S .

ΩDMh2 = ΩN1h2 +ΩSh2 ∆m = mN2 − mN1 ≈ mN± − mN1(sin

Purusottam Ghosh IIT Guwahati March 21, 2019 5 / 10

Relic and Direct search outcome

DM-DM Conversion

• Large ∆m = mN± − mN1 > 12 GeV is allowed in this two component

model which is otherway absent in single component VLF DM scenario.

Purusottam Ghosh IIT Guwahati March 21, 2019 6 / 10

Collider Signature of VLF DM at LHC , √s = 14 TeV

Signal :: p p → N+ N−, (N− → ℓ− νℓ N1), (N+ → ℓ+ νℓ N1) ℓ = e, µ

• Large ∆m allows MET

distribution peaking at high value.

• This helps in elliminations
• f SM background.

Purusottam Ghosh IIT Guwahati March 21, 2019 7 / 10

Summary

DM-DM interaction plays a crucial role and yields lagrer region of allowed parameter space of heavier DM component. Presence of scalar DM, large ∆m = mN± − mN1 region (upto 500 GeV) of VLF becomes allowed from relic and direct search bound which is otherway absent in single component VLF DM scenario. The signal of VLF DM can be observed at LHC at high Luminosity in presence of second lighter DM component.

Purusottam Ghosh IIT Guwahati March 21, 2019 8 / 10

Backup dYNi dx = −0.264MP l √g∗ µ x2

j

• σvNiNj →SM
• YNi YNj − Y EQ

Ni Y EQ Nj

• +σvNiNj →SS
• YNi YNj −

Y EQ

Ni Y EQ Nj

Y EQ

S 2

Y 2

S

• Θ(mNi + mNj − 2mS)

−σvSS→NiNj

• Y 2

S −

Y EQ

S 2

Y EQ

Ni Y EQ Nj

YNi YNj

• Θ(2mS − mNi − mNj )
• +σvNiN±→SM
• YNi YN± − Y EQ

Ni Y EQ N±

• ,

dYS dx = −0.264MP l √g∗ µ x2

• σvSS→SM
• YS

2 − Y EQ S 2

+

• i,j
• − σvNiNj →SS
• YNi YNj −

Y EQ

Ni Y EQ Nj

Y EQ

S 2

Y 2

S

• Θ(mNi + mNj − 2mS)

+σvSS→NiNj

• Y 2

S −

Y EQ

S 2

Y EQ

Ni Y EQ Nj

YNi YNj

• Θ(2mS − mNi − mNj )
• ,

(1) Purusottam Ghosh IIT Guwahati March 21, 2019 9 / 10

Backup

N1 N1

n n

Z N1 N1

n n

h S S

n n

h

Feynman diagrams of spin independent (SI) direct detection of fermion DM (left) and scalar DM (right). σSI

eff (N1) =

ΩN1 h2 ΩT h2

• σSI

N1 ,

σSI

eff (S) =

ΩSh2 ΩT h2

• σSI

S .

R =

• ntvρc

mφ

• ΩT σSI

T

=

• ntvρc

mφ1

• Ω1σDD

1

+

• ntvρc

mφ2

• Ω2σDD

2

, =

• ntvρc

mφ1

• [Ω1σDD

1

+ mφ1 mφ2 Ω2σDD

2

] ∴ σSI

T

= Ω1 ΩT σDD

1

+ Ω2 ΩT mφ1 mφ2

• σDD

2

. (2) Purusottam Ghosh IIT Guwahati March 21, 2019 10 / 10