probing kinetic mixing term of dark gauge boson at the lhc · 2019. 6. 4. · probing kinetic...
TRANSCRIPT
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Teruki Kamon Mitchell Institute for Fundamental Physics and Astronomy
Texas A&M University
Searching for Long-Lived Particles at the LHC:
Fifth workshop on the LHC Long-Lived Particle (LLP) Community,
(https://indico.cern.ch/event/792346/overview)
CERN, 27-29 May 2019
1May 27, 2019 Kinetic Mixing
[Credits]
Images of Baryon Acoustic Bscillations with Cosmic Microwave Background
by E.M. Huff, the SDSS-III team, and the South Pole Telescope team. Graphic
by Zosia Rostomian (Lawrence Berkeley National Laboratory)
Image of Neutrino Astrophysics, taken from https://astro.desy.de/
Image of the LHC by CERN Photo
Image of Bullet Cluster by NASA/ Chandra X-ray Center
Probing Kinetic Mixing Term
of Dark Gauge Boson
at the LHCCollaboration:
Mohammad Abdullah (Mitchell Institute)
Bhaskar Dutta (Mitchell Institute)
Teruki Kamon (CMS/Mitchell Institute)
Marcus Hohlmann (CMS/FIT)
Adrian Thompson (CMS/Mitchell Institute)
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A simple extension of the standard model involves adding a "dark" U(1) gauge group
that is broken by a dark Higgs vev. The "dark vector" 𝑍𝐷 can then kinetically mix withthe 𝑈(1)𝐵 gauge boson, and the "dark Higgs" 𝑆 (or ℎ𝑆) can mix with the SM doubletHiggs via the Higgs portal |H|2|S|2 operator. This can induce a variety of exotic Higgs
decays like:
ℎ → 𝑍𝑍𝐷 (if kinetic mixing dominates)ℎ → 𝑍𝐷𝑍𝐷 (if higgs mixing dominates)ℎ → 𝑆𝑆 (if higgs mixing dominates)
http://insti.physics.sunysb.edu/~curtin/hahm_mg.html
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Kinetic Mixing with Dark Gauge Boson
Note: this is not Feynman diagram
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Kinetic Mixing by ATLAS and CMS
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MC samples m(𝜸𝑫) = 0.25 –58 GeV 𝑐𝜏 = 0 –100 mm m(𝑵𝟏) = 10, 60 GeV, m(𝒏𝑫) = 1 GeV
Unknown
branching
fractions
Unknown
branching
fractions
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𝑝𝑝 → ℎ → 𝑍𝑍𝑑(or 𝑎𝑎) → 4𝓁 ; 𝑝𝑝 → 𝑍𝑑 → 𝓁𝓁; 𝑝𝑝 → 𝑍 → 𝜇𝜇; 𝑍𝑑 → 4𝓁
Other Representative Processes
Independent of the Higgs portal
|H|2|S|2 operator
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𝒁′ as ”𝜸𝒅 or 𝒁𝒅” Search FrameworkPhysics of dark gauge boson (𝜸𝑑 or 𝑍𝑑) can be studied via a framework of aspin-1 particle (𝒁′) which couples to first- and second-generation fermions.
o Associated production with ISR jet/photon or the SM weak
gauge boson (V = W or Z) will probe the mixing term
independently of the Higgs portal |H|2|S|2 operator.
o Larger signal cross sections, compared to processes with
the Higgs boson decays.
o [Trigger] A standard mono-jet or mono-photon or mutilepton
trigger (w/o vertex constraint on leptons).
o [Main backgrounds] g(photon)+𝛾∗ (𝑝𝑇(𝑔 𝑜𝑟 𝛾) > 200 GeV) or V+𝛾∗ (𝑝𝑇(𝑉) >
20 GeV), followed by 𝛾∗ → 𝜇𝜇. But they should be suppressed by a lifetime cut. Also 𝑔∗ → 𝑏𝑏 → 𝜇𝜇 + 𝑋 (we need an isolation study.)
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A basic idea on direct production is stated in “Non-Abelian
Dark Sectors and Their Collider Signatures”, Matthew
Baumgart, Clifford Cheung, Joshua T. Ruderman, Lian-Tao
Wang, and Itay Yavin, JHEP 04 (2009) 014, 10.1088/1126-
6708/2009/04/014 [arXiv:0901.0283]. See Fig. 11.
https://arxiv.org/ct?url=https%3A%2F%2Fdx.doi.org%2F10.1088%2F1126-6708%2F2009%2F04%2F014&v=50ff5ccehttps://arxiv.org/abs/0901.0283
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𝒁′ Associate Production Processes
𝑝𝑇(𝑔) > 200 GeV
𝑝𝑇(𝛾) > 200 GeV
𝑝𝑇(𝑉) > 20 GeV
𝑝𝑇(𝑉) > 20 GeV
Low mass 𝑍′ could be probed by V+𝑍′, as an angular separation of leptons in highlyboosted lighter dark gauge boson may be a problem in high 𝑝𝑇(𝑔 𝑜𝑟 𝛾) trigger. For𝑝𝑇 ≳ 200 GeV, an opening angle of approximately 𝜃~ Τ𝑚𝛾′ 𝑝𝑇 < 0.00125 for M = 0.25
GeV.
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Kinematics in 𝒁′ Associate Production𝒑𝑻(j,𝜸) > 200 GeV or 𝒑𝑻(𝝁 from W, Z) > 20 GeV
M = 1 GeV M = 10 GeV
𝒑𝑻(𝝁𝝁)
∆𝝋(𝝁𝝁)
𝒑𝑻(𝝁𝝁)
∆𝝋(𝝁𝝁)
MadGraph+Delphes
Adrian Thompson
Mohammad Abdullah
𝜃~ Τ𝑚𝛾′ 𝑝𝑇 < 0.005
for 1 GeV mass
𝝈∙𝑨∙ℒ
𝝈∙𝑨∙ℒ
𝝈∙𝑨∙ℒ
𝝈∙𝑨∙ℒ
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[U(1)𝐿𝜇 − 𝐿𝜏 gauge bosons] A search for Z′ in 4μ final state, PLB 792 (2019) 345, EXO
18-008, CMS AN-17/321, arXiv:1808.03684
[Refs: arxiv:1808.03647, arxiv:1712.10022]
70 GeV
Complementary Search
+ quark sectors?
?
[CMS, PLB 792 (2019) 345; 1808.03684] The
4μ analysis can set limits on 𝑔𝜇 for masses
down to 10 GeV.
𝒈
The limits will depend on how many decay
channels the Z‘ has in our model.
There are some limits from related searches,
but not on the same process directly.
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Summary[Complementary] The mixing term can
be probed via associate production with
ISR jet/photon or the SM weak gauge
boson (V = W or Z), independently of
the Higgs portal |H|2|S|2 operator.
[Wide mass range] Low mass 𝑍′ can besearched using V+𝑍′ (𝑝𝑇(𝑉) > 20 GeV),as angular separation of leptons in
highly boosted lighter dark gauge boson
may be a problem in 𝑝𝑇 𝑔 𝑜𝑟 𝛾 > 200 −500 GeV.
“Hunting All the Hidden Photons”, Martin
Bauer, Patrick Foldenauer, and Joerg Jaeckel,
JHEP 07 (2018) 094
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BACKUP
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Cross Section and AcceptanceMadGraph+Delphes
Adrian Thompson
Mohammad Abdullah
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Thinking of Direct ProductionA basic idea on direct production is stated in “Non-Abelian Dark Sectors and
Their Collider Signatures”, Matthew Baumgart, Clifford Cheung, Joshua T.
Ruderman, Lian-Tao Wang, and Itay Yavin, JHEP 04 (2009) 014,
10.1088/1126-6708/2009/04/014 [arXiv:0901.0283].
See Fig. 11. X is not specified. They envisioned to trigger those events with
single/dimuon triggers, referring to CMS Level 1 dimuon trigger (2 muons with 𝑝𝑇 > 3GeV in |η| < 2.4) or single muon trigger (1 muon with 𝑝𝑇 > 7 GeV and |η| < 2.4). Thus𝑝𝑇 ≳ 10 GeV, resulting in an opening angle of approximately 𝜃~ Τ𝑚𝛾′ 𝑝𝑇 < 0.025 for 10
GeV 𝑝𝑇, 0.25 GeV mass.
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https://arxiv.org/ct?url=https%3A%2F%2Fdx.doi.org%2F10.1088%2F1126-6708%2F2009%2F04%2F014&v=50ff5ccehttps://arxiv.org/abs/0901.0283
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On Decay ModesIf Gd includes SU(2)d, the decay modes are more complex.
See Fig. 9 of “Non-Abelian Dark Sectors and Their Collider Signatures”, Matthew
Baumgart, Clifford Cheung, Joshua T. Ruderman, Lian-Tao Wang, and Itay Yavin,
JHEP 04 (2009) 014, 10.1088/1126-6708/2009/04/014 [arXiv:0901.0283].
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https://arxiv.org/ct?url=https%3A%2F%2Fdx.doi.org%2F10.1088%2F1126-6708%2F2009%2F04%2F014&v=50ff5ccehttps://arxiv.org/abs/0901.0283
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Probing Kinetic Mixing Term at LHC“Hunting All the Hidden Photons”, Martin Bauer, Patrick Foldenauer, and
Joerg Jaeckel, JHEP 07 (2018) 094
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Can we search at ATLAS + CMS?𝝐𝒆
𝑴𝑨′
Physics of dark gauge boson (𝜸𝑑 or 𝑍𝑑) can be studied via a framework of a spin-1particle (𝒁′) which couples to first- and second-generation fermions.
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[U(1)𝑳𝝁 − 𝑳𝝉 gauge bosons] A search for Z′ in 4μ final state, PLB 792 (2019)
345, EXO 18-008, CMS AN-17/321, arXiv:1808.03684[Refs: arxiv:1808.03647, arxiv:1712.10022]
70 GeV
Example: Constraints on 𝒈𝝁 on 𝒁′
[CMS, PLB 792 (2019) 345; 1808.03684] The
4μ analysis can set limits on 𝑔𝜇 for masses
down to 10 GeV.
Also see [CMS, JHEP 01 (2018)
097;1710.00159] Z’ with AK8 jet 𝑝𝑇 > 500 GeV (against another high 𝑝𝑇 ISR jet) for leptophobic Z' that can set limits on 𝑔𝑞 down
to 𝑚(𝑍′) = 50 GeV.
𝒈
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“Coherent elastic neutrino nucleus scattering as a probe of a Z′ through kinetic and mass mixing
effects” Mohammad Abdullah, James B. Dent, Bhaskar Dutta, Gordon L. Kane, Shu Liao, and
Louis E. Strigari, Phys.Rev. D98 (2018) 015005
𝝐𝒁 𝝐𝑩
Connection with CEvNS