Abstract
The LHCb detector provides accurate vertex reconstruction and hadronic particle identification, which make the experiment an ideal place to look for light long-lived particles (LLP) decaying into Standard Model (SM) hadrons. In contrast with the typical search strategy relying on energetic jets and a high multiplicity of tracks from the LLP decay, LHCb can identify LLPs in exclusive, specific hadronic final states. To illustrate the idea, we study the sensitivity of LHCb to an exotic Higgs decay h → SS, followed by the displaced decay of GeV-scale scalars into charged kaons S → K+K−. We show that the reconstruction of kaon vertices in narrow invariant mass windows can efficiently eliminate the combinatorial backgrounds from B-meson decays. While the same signal is extremely difficult to probe in the existing displaced jet searches at ATLAS/CMS, the LHCb search we propose can probe the branching ratio BR(h → SS) down to 0.1% (0.02%) level with 15 (300) fb−1 of data. We also apply this projected bound to two scenarios with Higgs portal couplings, where the scalar mediator S either couples to a) the SM quarks only, or b) to both quarks and leptons in the minimal flavor violation paradigm. In both scenarios we compare the reach of our proposed search with the expected constraints from ATLAS and CMS on the invisible Higgs width and with the constraints from rare B-decays studies at LHCb. We find that for 1 GeV < mS< 2 GeV and 0.5 mm ≲ cτ ≲ 10 mm our proposed search will be competitive with the ATLAS and CMS projections, while at the same time providing crucial information of the hadronic interactions of S, which can not be obtained from the indirect measurement of the Higgs invisible width.
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References
M. Pospelov, A. Ritz and M.B. Voloshin, Secluded WIMP Dark Matter, Phys. Lett.B 662 (2008) 53 [arXiv:0711.4866] [INSPIRE].
G. Krnjaic, Probing Light Thermal Dark-Matter With a Higgs Portal Mediator, Phys. Rev.D 94 (2016) 073009 [arXiv:1512.04119] [INSPIRE].
P.S.B. Dev, R.N. Mohapatra and Y. Zhang, Long Lived Light Scalars as Probe of Low Scale Seesaw Models, Nucl. Phys.B 923 (2017) 179 [arXiv:1703.02471] [INSPIRE].
P. Fayet, Supergauge Invariant Extension of the Higgs Mechanism and a Model for the electron and Its Neutrino, Nucl. Phys.B 90 (1975) 104 [INSPIRE].
M. Shaposhnikov and I. Tkachev, The nuMSM, inflation and dark matter, Phys. Lett.B 639 (2006) 414 [hep-ph/0604236] [INSPIRE].
F. Bezrukov and D. Gorbunov, Light inflaton Hunter’s Guide, JHEP05 (2010) 010 [arXiv:0912.0390] [INSPIRE].
P.W. Graham, D.E. Kaplan and S. Rajendran, Cosmological Relaxation of the Electroweak Scale, Phys. Rev. Lett.115 (2015) 221801 [arXiv:1504.07551] [INSPIRE].
J. Alimena et al., Searching for Long-Lived Particles beyond the Standard Model at the Large Hadron Collider, arXiv:1903.04497 [INSPIRE].
CMS collaboration, Search for long-lived particles decaying into displaced jets in proton-proton collisions at \( \sqrt{s} \) = 13 TeV, Phys. Rev.D 99 (2019) 032011 [arXiv:1811.07991] [INSPIRE].
CMS collaboration, Search for new particles decaying to a jet and an emerging jet, CMS-PAS-EXO-18-001 (2018) [INSPIRE].
ATLAS collaboration, Search for long-lived particles produced in pp collisions at \( \sqrt{s} \) = 13 TeV that decay into displaced hadronic jets in the ATLAS muon spectrometer, Phys. Rev.D 99 (2019) 052005 [arXiv:1811.07370] [INSPIRE].
ATLAS collaboration, Search for long-lived neutral particles in pp collisions at \( \sqrt{s} \) = 13 TeV that decay into displaced hadronic jets in the ATLAS calorimeter, Eur. Phys. J.C 79 (2019) 481 [arXiv:1902.03094] [INSPIRE].
ATLAS collaboration, Search for light long-lived neutral particles produced in pp collisions at \( \sqrt{s} \) = 13 TeV and decaying into collimated leptons or light hadrons with the ATLAS detector, arXiv:1909.01246 [INSPIRE].
LHCb collaboration, Updated search for long-lived particles decaying to jet pairs, Eur. Phys. J.C 77 (2017) 812 [arXiv:1705.07332] [INSPIRE].
D. Curtin et al., Exotic decays of the 125 GeV Higgs boson, Phys. Rev.D 90 (2014) 075004 [arXiv:1312.4992] [INSPIRE].
ATLAS collaboration, Combination of searches for invisible Higgs boson decays with the ATLAS experiment, Phys. Rev. Lett.122 (2019) 231801 [arXiv:1904.05105] [INSPIRE].
CMS collaboration, Search for invisible decays of a Higgs boson produced through vector boson fusion in proton-proton collisions at \( \sqrt{s} \) = 13 TeV, Phys. Lett.B 793 (2019) 520 [arXiv:1809.05937] [INSPIRE].
F. Yu, Anatomizing Exotic Production of the Higgs Boson, Phys. Rev.D 90 (2014) 015009 [arXiv:1404.2924] [INSPIRE].
A. Pierce, B. Shakya, Y. Tsai and Y. Zhao, Searching for confining hidden valleys at LHCb, ATLAS and CMS, Phys. Rev.D 97 (2018) 095033 [arXiv:1708.05389] [INSPIRE].
LHCb collaboration, LHCb Detector Performance, Int. J. Mod. Phys.A 30 (2015) 1530022 [arXiv:1412.6352] [INSPIRE].
LHCb collaboration, Search for Dark Photons Produced in 13 TeV pp Collisions, Phys. Rev. Lett.120 (2018) 061801 [arXiv:1710.02867] [INSPIRE].
LHCb collaboration, Search for massive long-lived particles decaying semileptonically in the LHCb detector, Eur. Phys. J.C 77 (2017) 224 [arXiv:1612.00945] [INSPIRE].
LHCb collaboration, LHCb Trigger and Online Upgrade Technical Design Report, CERN-LHCC-2014-016 (2014) [LHCB-TDR-016] [INSPIRE].
LHCb collaboration, Expression of Interest for a Phase-II LHCb Upgrade: Opportunities in flavour physics and beyond, in the HL-LHC era, CERN-LHCC-2017-003 (2017).
M. Adinolfi et al., Performance of the LHCb RICH detector at the LHC, Eur. Phys. J.C 73 (2013) 2431 [arXiv:1211.6759] [INSPIRE].
LHCb collaboration, LHCb PID Upgrade Technical Design Report, CERN-LHCC-2013-022 (2013) [LHCB-TDR-014] [INSPIRE].
LHCb collaboration, LHCb VELO Upgrade Technical Design Report, CERN-LHCC-2013-021 (2013) [LHCB-TDR-013] [INSPIRE].
LHCb collaboration, Measurement of the inclusive 𝜙 cross-section in pp collisions at \( \sqrt{s} \) = 7 TeV, Phys. Lett.B 703 (2011) 267 [arXiv:1107.3935] [INSPIRE].
LHCb collaboration, Observation of the decay \( {B}_s^0 \)→ ηc𝜙 and evidence for B0 → ηcπ+ π− , s s JHEP07 (2017) 021 [arXiv:1702.08048] [INSPIRE].
LHCb collaboration, Search for direct CP-violation in D0→ h−h+modes using semileptonic B decays, Phys. Lett.B 723 (2013) 33 [arXiv:1303.2614] [INSPIRE].
X. Cid Vidal, P. Ilten, J. Plews, B. Shuve and Y. Soreq, Discovering True Muonium at LHCb, Phys. Rev.D 100 (2019) 053003 [arXiv:1904.08458] [INSPIRE].
LHCb collaboration, Framework TDR for the LHCb Upgrade: Technical Design Report, CERN-LHCC-2012-007 (2012) [LHCb-TDR-12] [INSPIRE].
A. Puig, The LHCb trigger in 2011 and 2012, LHCb-PUB-2014-046 (2014) [CERN-LHCb-PUB-2014-046].
LHCb collaboration, Design and performance of the LHCb trigger and full real-time reconstruction in Run 2 of the LHC, 2019 JINST14 P04013 [arXiv:1812.10790] [INSPIRE].
T. Sjöstrand, S. Mrenna and P.Z. Skands, A Brief Introduction to PYTHIA 8.1, Comput. Phys. Commun.178 (2008) 852 [arXiv:0710.3820] [INSPIRE].
M.W. Winkler, Decay and detection of a light scalar boson mixing with the Higgs boson, Phys. Rev.D 99 (2019) 015018 [arXiv:1809.01876] [INSPIRE].
G. D’Ambrosio, G.F. Giudice, G. Isidori and A. Strumia, Minimal flavor violation: An Effective field theory approach, Nucl. Phys.B 645 (2002) 155 [hep-ph/0207036] [INSPIRE].
LHCb collaboration, Measurement of the b-quark production cross-section in 7 and 13 TeV pp collisions, Phys. Rev. Lett.118 (2017) 052002 [Erratum ibid.119 (2017) 169901] [arXiv:1612.05140] [INSPIRE].
M. Alexander et al., Mapping the material in the LHCb vertex locator using secondary hadronic interactions, 2018 JINST13 P06008 [arXiv:1803.07466] [INSPIRE].
LHCb collaboration, Prompt K0production in pp collisions at \( \sqrt{s} \) = 0.9 TeV, Phys. Lett.B 693 (2010) 69 [arXiv:1008.3105] [INSPIRE].
LHCb collaboration, Measurement of V0production ratios in pp collisions at \( \sqrt{s} \) = 0.9 and 7 TeV, JHEP08 (2011) 034 [arXiv:1107.0882] [INSPIRE].
M. Cepeda et al., Report from Working Group 2, CERN Yellow Rep. Monogr.7 (2019) 221 [arXiv:1902.00134] [INSPIRE].
LHCb collaboration, Search for long-lived scalar particles in B+→ K+χ(μ+μ− ) decays, Phys. Rev.D 95 (2017) 071101 [arXiv:1612.07818] [INSPIRE].
LHCb collaboration, Search for hidden-sector bosons in B0→ K∗0μ+μ−decays, Phys. Rev. Lett.115 (2015) 161802 [arXiv:1508.04094] [INSPIRE].
CMS collaboration, A search for pair production of new light bosons decaying into muons at \( \sqrt{s} \) = 13 TeV, CMS-PAS-HIG-18-003 (2018) [INSPIRE].
S. Raby and G.B. West, The Branching Ratio for a Light Higgs to Decay Into μ+μ−Pairs, Phys. Rev.D 38 (1988) 3488 [INSPIRE].
T.N. Truong and R.S. Willey, Branching Ratios for Decays of Light Higgs Bosons, Phys. Rev.D 40 (1989) 3635 [INSPIRE].
J.F. Donoghue, J. Gasser and H. Leutwyler, The Decay of a Light Higgs Boson, Nucl. Phys.B 343 (1990) 341 [INSPIRE].
F. Bezrukov, D. Gorbunov and I. Timiryasov, Uncertainties of hadronic scalar decay calculations, arXiv:1812.08088 [INSPIRE].
C. Bird, P. Jackson, R.V. Kowalewski and M. Pospelov, Search for dark matter in b → s transitions with missing energy, Phys. Rev. Lett.93 (2004) 201803 [hep-ph/0401195] [INSPIRE].
J.D. Clarke, R. Foot and R.R. Volkas, Phenomenology of a very light scalar (100 MeV < mh < 10 GeV) mixing with the SM Higgs, JHEP02 (2014) 123 [arXiv:1310.8042] [INSPIRE].
K. Schmidt-Hoberg, F. Staub and M.W. Winkler, Constraints on light mediators: confronting dark matter searches with B physics, Phys. Lett.B 727 (2013) 506 [arXiv:1310.6752] [INSPIRE].
J.A. Evans, S. Gori and J. Shelton, Looking for the WIMP Next Door, JHEP02 (2018) 100 [arXiv:1712.03974] [INSPIRE].
I. Boiarska, K. Bondarenko, A. Boyarsky, V. Gorkavenko, M. Ovchynnikov and A. Sokolenko, Phenomenology of GeV-scale scalar portal, JHEP11 (2019) 162 [arXiv:1904.10447] [INSPIRE].
I. Boiarska, K. Bondarenko, A. Boyarsky, M. Ovchynnikov, O. Ruchayskiy and A. Sokolenko, Light scalar production from Higgs bosons and FASER 2, arXiv:1908.04635 [INSPIRE].
S. Knapen, T. Lin and K.M. Zurek, Light Dark Matter: Models and Constraints, Phys. Rev.D 96 (2017) 115021 [arXiv:1709.07882] [INSPIRE].
B. Batell, A. Freitas, A. Ismail and D. Mckeen, Flavor-specific scalar mediators, Phys. Rev.D 98 (2018) 055026 [arXiv:1712.10022] [INSPIRE].
B. Batell, A. Freitas, A. Ismail and D. Mckeen, Probing Light Dark Matter with a Hadrophilic Scalar Mediator, Phys. Rev.D 100 (2019) 095020 [arXiv:1812.05103] [INSPIRE].
J. Liu, N. Weiner and W. Xue, Signals of a Light Dark Force in the Galactic Center, JHEP08 (2015) 050 [arXiv:1412.1485] [INSPIRE].
D. Curtin et al., Long-Lived Particles at the Energy Frontier: The MATHUSLA Physics Case, Rept. Prog. Phys.82 (2019) 116201 [arXiv:1806.07396] [INSPIRE].
J.L. Feng, I. Galon, F. Kling and S. Trojanowski, ForwArd Search ExpeRiment at the LHC, Phys. Rev.D 97 (2018) 035001 [arXiv:1708.09389] [INSPIRE].
V.V. Gligorov, S. Knapen, M. Papucci and D.J. Robinson, Searching for Long-lived Particles: A Compact Detector for Exotics at LHCb, Phys. Rev.D 97 (2018) 015023 [arXiv:1708.09395] [INSPIRE].
ATLAS collaboration, Search for pair-produced long-lived neutral particles decaying in the ATLAS hadronic calorimeter in pp collisions at \( \sqrt{s} \) = 8 TeV, Phys. Lett.B 743 (2015) 15 [arXiv:1501.04020] [INSPIRE].
ATLAS collaboration, Search for long-lived, weakly interacting particles that decay to displaced hadronic jets in proton-proton collisions at \( \sqrt{s} \) = 8 TeV with the ATLAS detector, Phys. Rev.D 92 (2015) 012010 [arXiv:1504.03634] [INSPIRE].
ATLAS collaboration, Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at \( \sqrt{s} \) = 8 TeV with the ATLAS detector, Phys. Rev.D 92 (2015) 072004 [arXiv:1504.05162] [INSPIRE].
ATLAS collaboration, Search for long-lived, massive particles in events with displaced vertices and missing transverse momentum in \( \sqrt{s} \) = 13 TeV pp collisions with the ATLAS detector, Phys. Rev.D 97 (2018) 052012 [arXiv:1710.04901] [INSPIRE].
CMS collaboration, Search for Long-Lived Neutral Particles Decaying to Quark-Antiquark Pairs in Proton-Proton Collisions at \( \sqrt{s} \) = 8 TeV, Phys. Rev.D 91 (2015) 012007 [arXiv:1411.6530] [INSPIRE].
CMS collaboration, Search for new long-lived particles at \( \sqrt{s} \) = 13 TeV, Phys. Lett.B 780 (2018) 432 [arXiv:1711.09120] [INSPIRE].
CMS collaboration, Search for long-lived particles with displaced vertices in multijet events in proton-proton collisions at \( \sqrt{s} \) = 13 TeV, Phys. Rev.D 98 (2018) 092011 [arXiv:1808.03078] [INSPIRE].
LHCb collaboration, Search for Higgs-like bosons decaying into long-lived exotic particles, Eur. Phys. J.C 76 (2016) 664 [arXiv:1609.03124] [INSPIRE].
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Vidal, X.C., Tsai, Y. & Zurita, J. Exclusive displaced hadronic signatures in the LHC forward region. J. High Energ. Phys. 2020, 115 (2020). https://doi.org/10.1007/JHEP01(2020)115
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DOI: https://doi.org/10.1007/JHEP01(2020)115