Dark matter motivated collider signatures in left-right - - PowerPoint PPT Presentation

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

Dark matter motivated collider signatures in left-right supersymmetry

Harri Waltari

University of Southampton & Rutherford Appleton Laboratory & NExT Institute University of Helsinki & Helsinki Institute of Physics

Southampton 23/10/2018

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

This talk should answer the questions What is left-right symmetry? How do you build a left-right symmetric supersymmetric model? What are the possible dark matter candidates in left-right supersymmetry? How can you find them at the LHC? This talk is based on 1702.02112 (MF,BF,KH,SKR,HW) and 1810.03891 together with Arindam Chatterjee, Mariana Frank, Benjamin Fuks, Katri Huitu, Subhadeep Mondal and Santosh Kumar Rai.

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

What is left-right symmetry?

The basic idea of left-right (LR) symmetry is that parity is a symmetry of Nature, which is spontaneously broken in weak interactions The gauge group must be extended to include right-handed weak interactions The generalization of electric charge is Q = I3L + I3R + (B − L)/2 The gauge group of left-right symmetric models is SU(3)c×SU(2)L×SU(2)R×U(1)B−L The gauge group of left-right symmetry can come e.g. from the breaking of SO(10)

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

LR symmetric models have right-handed doublets

The left-handed matter is in doublets of SU(2)L as usual Left-right symmetry then implies that right-handed matter should also be in doublets of SU(2)R The right-handed neutrinos must be included ⇒ Dirac masses for neutrinos can be introduced (normal type-I seesaw forbidden by gauge symmetry!) The usual R-parity violating couplings of the MSSM are forbidden due to the B − L symmetry

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

There are lots of Higgses in LR models

To generate masses for fermions you need a Higgs field that is in the (2,2) representation of SU(2)L×SU(2)R Using only one bidoublet doesn’t lead to the correct pattern of masses and CKM-mixings ⇒ another bidoublet If only bidoublets are around, m(WL) = m(WR) ⇒ Need for Higgs fields that are singlets under SU(2)L and not under SU(2)R We choose triplets (⇒ seesaw mass term for νR) of SU(2)R with B − L = 2 ⇒ anomaly cancellation requires a triplet with B − L = −2 and LR symmetry the corresponding triplets of SU(2)L The addition of a singlet is also phenomenologically motivated (breaking of SU(2)R and breaking of SUSY are independent) Altogether nine CP-even, seven CP-odd, six singly charged and four doubly charged Higgses

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

The desired vacuum structure would be a neutral one. . .

Φ1 = ϕ0

1

ϕ+

1

ϕ−

1

ϕ

′0

1

• →
• vd/

√ 2

• Φ2

=

• ϕ

′0

2

ϕ+

2

ϕ−

2

ϕ0

2

• →

vu/ √ 2

• ∆1R

=

• δ−

1R/

√ 2 δ0

1R

δ−−

1R

−δ−

1R/

√ 2

• →
• v1R/

√ 2

• ∆2R

= δ+

2R/

√ 2 δ++

2R

δ0

2R

−δ+

2R/

√ 2

• →
• v2R/

√ 2

• S

→ vS/ √ 2, ∆1L = ∆2L = 0. Terms proportional to viv ′

i lead to WL-WR mixing, which is known to be

very small.

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

. . . but it is often unstable

The determinant of the doubly charged Higgs mass matrix is negative if the triplet has a VEV ⇒ not a problem for ∆L (can be inert), but a definite problem for ∆R There are several proposed solutions: Spontaneous R-parity violation (˜ νR VEVs) [Kuchimanchi, Mohapatra, hep-ph/9306290] Nonrenormalizable operators [Mohapatra, Rasin, hep-ph/9511391, Aulakh et. al., hep-ph/9707256] Adding triplets with B − L = 0 [Aulakh et. al., hep-ph/9703434, hep-ph/9712551] Radiative corrections [Babu, Mohapatra, 0807.0481] We choose the last option in our work to have a viable dark matter candidate and to have the gauge sector within the reach of the LHC.

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

Neutralinos and right-handed sneutrinos are viable dark matter candidates

The viable classes of dark matter candidates are neutralinos and right-handed sneutrinos Left-handed sneutrinos are excluded like in the MSSM Of the various neutralino options we have considered gaugino and bidoublet higgsino dark matter Gaugino dark matter works only through resonant annihilation close to mh/2, all other regions produce too much dark matter The bidoublet higgsinos (four neutralinos and two charginos) always nearly degenerate, so coannihilation effects need to be taken into account The higgsino case points towards mDM ≃ 700 GeV, a heavy and compressed spectrum, a nightmare for collider searches

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

Right-handed sneutrinos annihilate via gauge interactions

The RH sneutrinos are a part of a doublet so they have a coupling to the SM-like Higgs, which is essentially a gauge coupling The coupling is so strong that no resonant annihilation is needed This coupling gives the leading annihilation channel, if RH neutrinos are lighter than the sneutrino, also a t-channel neutralino exchange will contribute Without coannihilations the mass of the sneutrino is the only free parameter ⇒ relic density predicts the sneutrino mass

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

The only viable solution is close to 250 GeV

Relic density constraints give two solutions but the lighter one is excluded by direct detection experiments Also the heavier one is close to being excluded

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

Coannihilations allow a wider range of sneutrino LSP masses

Coannhilations with fermions increase the effective annihilation cross section (⇒ heavier LSP mass), while coannihilations with other scalars decrease it Sneutrino LSP masses up to 700 GeV possible with coannihilating (4˜ χ0+2˜ χ±) higgsinos, above that neutralinos become the LSP

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

The WR has a large branching ratio to SUSY decay modes

Production cross section for sneutrinos or neutralinos/charginos very low, also the Higgs branching ratio h → ˜ χ˜ χ only 0.4% for the gaugino-like LSP Superpartners can be produced in the decays of WR or Z ′ of which the former is always lighter in LRSUSY Branching ratio to neutralino-chargino pairs (bidoublet higgsinos) ∼ 22%, slepton-sneutrino pairs a few percent Idea: Fix spectrum from the relic density constraint and look at WR decays to sleptons (no coannihilations) or neutralino-chargino pairs (coannihilations) For the simple setup we did a selection of cuts of our own, for the coannihilation case we recasted an existing LHC analysis (CMS-SUS-16-039, 1709.05406)

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

We have a set of benchmarks for various DM scenarios

Benchmark LSP m(LSP) m(NLSP) m(WR) BP1 ˜ ντ 278 609 3510 BP3 ˜ ντ 388 406 3370 BP5 ˜ H0 690 712 3370 Gaugino ˜ B– ˜ WR mix 62 300 3510 BP1: sneutrino LSP without coannihilations, BP3: sneutrino LSP coannihilating with higgsinos, BP5: higgsinos coannihilating with each

• ther, Gaugino: bino-wino mixture LSP without coannihilations; further

benchmarks in the articles

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

The signal topologies have several leptons and MET

SR Requirements A44 Nℓ = 3, Nτ = 0, NOSSF ≥ 1, MT > 160 GeV, / E T ≥ 200 GeV, Mℓℓ ≥ 105 GeV C18 Nℓ = 2, Nτ = 1, NOSSF = 1, MT2 > 100 GeV, / E T ≥ 200 GeV, Mℓℓ ≥ 105 GeV D16 Nℓ = 2, Nτ = 1, NOS = 1, NSF = 0, MT2 > 100 GeV, / E T ≥ 200 GeV G05 Nℓ ≥ 4, Nτ = 0, NOSSF ≥ 2, / E T ≥ 200 GeV H04 Nℓ ≥ 4, Nτ = 0, NOSSF < 2, / E T ≥ 150 GeV Dilepton Nℓ ≥ 2, / E T > 250 GeV, pT(ℓ1) > 200 GeV, pT(ℓ2) > 40 GeV, MT(ℓ1, / E T) > 250 GeV, MT(ℓ2, / E T) > 50 GeV, Nj ≤ 3, b-veto Table : Definition of the signal regions (SR) of the CMS analysis that we use as potentially best probes of our DM-favored LRSUSY scenarios.

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

The HL-LHC can probe LRSUSY as long as WR is not too heavy

BP1 BP3 BP5 Gaugino

• Int. lumi (fb−1)

300(3000)[100] 300(3000) 300(3000) 100 A44 0.74 (0.91) 0.91 (1.13) 0.42 (0.51) – C18 0.87 (1.08) 1.39 (1.79) 0.28 (0.33) – D16 2.55 (7.35) 2.41 (6.91) 1.74 (4.70) – G05 0.04 (0.06) 0.19 (0.27) 0.19 (0.27) – H04 0.04 (0.05) 0.31 (0.39) 0.26 (0.32) – Dilepton [3.0] – – 1.9

Table : Statistical significance S = S/

• S + B + σ2

B at the 13 TeV LHC for

the benchmarks under investigation.

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

The HL-LHC can probe LRSUSY as long as WR is not too heavy

Notice: If WR is found through some other channel, cuts can be

• ptimized to find SUSY decay modes and the reach could be better
• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry

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Introduction to left-right symmetry Dark matter candidates in LRSUSY Collider signatures

Summary

Left-right symmetric models provide explanations for parity violation, neutrino masses, R-parity conservation etc. The LRSUSY model has several viable dark matter candidates: gaugino-like neutralino, higgsino-like neutralino, right-handed sneutrino If the right-handed gauge sector is not too heavy, superpartners can be produced in the decays of WR Multilepton searches will be sensitive to LRSUSY at least up to WR masses of ∼ 4 TeV

• H. Waltari

Dark matter motivated collider signatures in left-right supersymmetry