CMS-PAS-EXO-20-005 | ||
Search for dark photons in VBF Higgs events in proton-proton collisions at √s= 13 TeV | ||
CMS Collaboration | ||
July 2020 | ||
Abstract: A search is presented for a Higgs boson that is produced via vector boson fusion and that decays to an undetected particle and an isolated photon. The search is performed by the CMS Collaboration at the Large Hadron Collider, using a data set corresponding to an integrated luminosity of 130 fb−1 recorded at a center-of-mass energy of 13 TeV. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for vector boson fusion production and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a Higgs boson mass of 125 GeV, assuming the standard model production rates, a combination with previous searches further reduces the observed (expected) 95% confidence level upper limit on the branching fraction to 2.9 (2.1)%. This is the first search for such decays in the vector boson fusion channel. The results improve significantly the constraints on this decay mode. | ||
Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, JHEP 03 (2021) 011. The superseded preliminary plots can be found here. |
Figures | |
![]() png pdf |
Figure 1:
A Feynman diagram for the production of the qqH(→γγD) final state. |
![]() png pdf |
Figure 2:
The mjj distributions from the simultaneous fit with the full data set in the γ+jets CRs (top left), Z(ℓˉℓ)+γ CRs (top right), and W(→ℓν)+γ CRs (bottom). Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 2-a:
The mjj distributions from the simultaneous fit with the full data set in the γ+jets CRs. Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 2-b:
The mjj distributions from the simultaneous fit with the full data set in the Z(ℓˉℓ)+γ CRs. Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 2-c:
The mjj distributions from the simultaneous fit with the full data set in the W(→ℓν)+γ CRs. Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 3:
The mT distributions from the simultaneous fit with the full data set for events with mjj< 1500 GeV in the W+jets CRs (top left), for events with mjj≥ 1500 GeV in the W+jets CRs (top right), for events with mjj< 1500 GeV in the SRs (bottom left), and for events with mjj≥ 1500 GeV in the SRs (bottom right). Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 3-a:
The mT distribution from the simultaneous fit with the full data set for events with mjj< 1500 GeV in the W+jets CRs. Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 3-b:
The mT distribution from the simultaneous fit with the full data set for events with mjj≥ 1500 GeV in the W+jets CRs. Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 3-c:
The mT distribution from the simultaneous fit with the full data set for events with mjj< 1500 GeV in the SRs. Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 3-d:
The mT distribution from the simultaneous fit with the full data set for events with mjj≥ 1500 GeV in the SRs. Overflow events are included in the last bin. The gray bands represent the uncertainties in the predicted yields. A hollow green shape indicates the contribution expected from inclusive SM Higgs boson production assuming a semi-visible branching ratio of 5%. |
![]() png pdf |
Figure 4:
Expected and observed upper limits at 95% CL on the product of σVBF and B(H→invisible+γ) as a function of mH. The dot-dashed line shows the predicted signal corresponding to 0.05σVBF, assuming VBF production only. A linear interpolation is performed between the values obtained for the probed Higgs boson masses. |
Tables | |
![]() png pdf |
Table 1:
Summary of the selection criteria in the signal region depending on the trigger path and data-taking year. Rows with one value indicates that the same requirement is applied for all data-taking years. |
![]() png pdf |
Table 2:
Summary of the binning choice in the SRs and CRs. |
![]() png pdf |
Table 3:
Data, expected backgrounds, and signal in the different regions. The signal size is chosen to be 0.05×σSM, where σSM is the SM Higgs boson cross section for mH= 125 GeV. All data-taking periods and trigger paths are combined together for each region. |
![]() png pdf |
Table 4:
Observed and expected 95% CL limits at mH= 125 GeV on B(H→invisible+γ) for the VBF category, ZH category, and their combination. |
Summary |
A search has been presented for a Higgs boson that is produced via vector boson fusion and that decays to an undetected particle together with an isolated photon. This is the first search for this signature. The search has been performed by the CMS Collaboration using a data set corresponding to an integrated luminosity of 130 fb−1 recorded at a center-of-mass energy of 13 TeV. No significant excess of events above the expectation from the standard model background is found. The results are used to place limits on the product of the signal cross section for VBF production and the branching fraction for such decays of the Higgs boson, in the context of a theoretical model where the undetected particle is a massless dark photon. Allowing for deviations from standard model VBF production, the product of σVBF and B(H→invisible+γ) is excluded above ∼150 to ∼2 fb, for mH ranging from 125 to 1000 GeV. By combining with an existing analysis targeting associated Z boson production, and assuming the standard model rates, the observed (expected) upper limits at 95% confidence level at mH= 125 GeV on B(H→invisible+γ) is 2.9 (2.1)%. |
References | ||||
1 | ATLAS Collaboration | Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC | PLB 716 (2012) 1 | 1207.7214 |
2 | CMS Collaboration | Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC | PLB 716 (2012) 30 | CMS-HIG-12-028 1207.7235 |
3 | CMS Collaboration | Observation of a new boson with mass near 125 GeV in pp collisions at √s= 7 and 8 TeV | JHEP 06 (2013) 081 | CMS-HIG-12-036 1303.4571 |
4 | D. Ghosh et al. | Looking for an invisible Higgs signal at the LHC | PLB 725 (2013) 344 | 1211.7015 |
5 | S. P. Martin and J. D. Wells | Motivation and detectability of an invisibly decaying Higgs boson at the Fermilab Tevatron | PRD 60 (1999) 035006 | hep-ph/9903259 |
6 | Y. Bai, P. Draper, and J. Shelton | Measuring the invisible Higgs width at the 7 and 8 TeV LHC | JHEP 07 (2012) 192 | 1112.4496 |
7 | D. Curtin et. al. | Exotic decays of the 125 GeV Higgs boson | PRD 90 (2014) 075004 | 1312.4992 |
8 | ATLAS, CMS Collaboration | Combined Measurement of the Higgs Boson Mass in pp Collisions at √s= 7 and 8 TeV with the ATLAS and CMS Experiments | PRL 114 (2015) 191803 | 1503.07589 |
9 | CMS Collaboration | Measurements of properties of the Higgs boson decaying into the four-lepton final state in pp collisions at √s= 13 TeV | JHEP 11 (2017) 047 | CMS-HIG-16-041 1706.09936 |
10 | ATLAS, CMS Collaboration | Measurements of the Higgs boson production and decay rates and constraints on its couplings from a combined ATLAS and CMS analysis of the LHC pp collision data at √s= 7 and 8 TeV | JHEP 08 (2016) 045 | 1606.02266 |
11 | CMS Collaboration | Combined measurements of Higgs boson couplings in proton-proton collisions at √s= 13 TeV | EPJC 79 (2019) 421 | CMS-HIG-17-031 1809.10733 |
12 | A. Djouadi and M. Drees | Higgs boson decays into light gravitinos | PLB 407 (1997) 243 | hep-ph/9703452 |
13 | C. Petersson, A. Romagnoni, and R. Torre | Higgs decay with monophoton + ⧸ET signature from low scale supersymmetry breaking | JHEP 10 (2012) 016 | 1203.4563 |
14 | E. Gabrielli and M. Raidal | Exponentially spread dynamical Yukawa couplings from nonperturbative chiral symmetry breaking in the dark sector | PRD 89 (2014) 015008 | 1310.1090 |
15 | E. Gabrielli, M. Heikinheimo, B. Mele, and M. Raidal | Dark photons and resonant monophoton signatures in Higgs boson decays at the LHC | PRD 90 (2014) 055032 | 1405.5196 |
16 | S. Biswas, E. Gabrielli, M. Heikinheimo, and B. Mele | Dark-photon searches via Higgs-boson production at the LHC | PRD 93 (2016) 093011 | 1603.01377 |
17 | S. Biswas, E. Gabrielli, M. Heikinheimo, and B. Mele | Searching for massless dark-photons at the LHC via Higgs boson production | in Proceedings, 2017 European Physical Society Conference on High Energy Physics (EPS-HEP 2017), Venice, Italy, 2017 | |
18 | D. de Florian et al. | Handbook of LHC Higgs cross sections: 4. Deciphering the nature of the Higgs sector | CERN-2017-002-M | 1610.07922 |
19 | CMS Collaboration | Search for exotic decays of a Higgs boson into undetectable particles and one or more photons | PLB 753 (2016) 363 | CMS-HIG-14-025 1507.00359 |
20 | CMS Collaboration | Search for dark photons in decays of Higgs bosons produced in association with Z bosons in proton-proton collisions at √s= 13 TeV | JHEP 10 (2019) 139 | CMS-EXO-19-007 1908.02699 |
21 | CMS Collaboration | The CMS Experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
22 | CMS Collaboration | The CMS trigger system | JINST 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
23 | S. Frixione and B. R. Webber | Matching NLO QCD computations and parton shower simulations | JHEP 06 (2002) 029 | hep-ph/0204244 |
24 | P. Nason | A new method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 11 (2004) 040 | hep-ph/0409146 |
25 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with parton shower simulations: the POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
26 | S. Alioli, P. Nason, C. Oleari, and E. Re | NLO vector-boson production matched with shower in POWHEG | JHEP 07 (2008) 060 | 0805.4802 |
27 | S. Alioli, P. Nason, C. Oleari, and E. Re | A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX | JHEP 06 (2010) 043 | 1002.2581 |
28 | S. Heinemeyer et al. | Handbook of LHC Higgs cross sections: 3. Higgs properties | CERN-2013-004 | 1307.1347 |
29 | T. Sjostrand, S. Mrenna, and P. Z. Skands | A brief introduction to PYTHIA 8.1 | CPC 178 (2008) 852 | 0710.3820 |
30 | J. Alwall et al. | The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations | JHEP 07 (2014) 079 | 1405.0301 |
31 | J. Alwall et al. | MadGraph 5: going beyond | JHEP 06 (2011) 128 | 1106.0522 |
32 | R. Frederix and S. Frixione | Merging meets matching in MC@NLO | JHEP 12 (2012) 061 | 1209.6215 |
33 | J. Alwall et al. | Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions | EPJC 53 (2008) 473 | 0706.2569 |
34 | NNPDF Collaboration | Parton distributions for the LHC Run II | JHEP 04 (2015) 040 | 1410.8849 |
35 | NNPDF Collaboration | Parton distributions from high-precision collider data | EPJC 77 (2017) 663 | 1706.00428 |
36 | P. Skands, S. Carrazza, and J. Rojo | Tuning PYTHIA 8.1: the Monash 2013 tune | EPJC 74 (2014) 3024 | 1404.5630 |
37 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
38 | CMS Collaboration | Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements | EPJC 80 (2020) 4 | CMS-GEN-17-001 1903.12179 |
39 | \GEANTfour Collaboration | GEANT4 --- a simulation toolkit | NIMA 506 (2003) 250 | |
40 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
41 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-kT jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
42 | CMS Collaboration | Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV | JINST 12 (2017) P02014 | CMS-JME-13-004 1607.03663 |
43 | CMS Collaboration | Jet energy scale and resolution performance with 13 TeV data collected by CMS in 2016-2018 | CDS | |
44 | CMS Collaboration | Pileup mitigation at CMS in 13 TeV data | Submitted to JINST | CMS-JME-18-001 2003.00503 |
45 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet user manual | EPJC 72 (2012) 1896 | 1111.6097 |
46 | CMS Collaboration | Performance of the CMS missing transverse momentum reconstruction in pp data at √s= 8 TeV | JINST 10 (2015) P02006 | CMS-JME-13-003 1411.0511 |
47 | CMS Collaboration | Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at √s= 8 TeV | JINST 10 (2015) P06005 | CMS-EGM-13-001 1502.02701 |
48 | CMS Collaboration | Electron and photon performance in CMS with the full 2017 data sample and additional 2016 highlights for the CALOR 2018 Conference | CDS | |
49 | CMS Collaboration | Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at √s= 13 TeV | JINST 13 (2018) P06015 | CMS-MUO-16-001 1804.04528 |
50 | CMS Collaboration | Performance of photon reconstruction and identification with the CMS Detector in proton-proton collisions at √s= 8 TeV | JINST 10 (2015) P08010 | CMS-EGM-14-001 1502.02702 |
51 | CMS Collaboration | Search for new physics in final states with a single photon and missing transverse momentum in proton-proton collisions at √s= 13 TeV | JHEP 02 (2019) 074 | CMS-EXO-16-053 1810.00196 |
52 | CMS Collaboration | Search for new physics in final states with an energetic jet or a hadronically decaying W or Z boson and transverse momentum imbalance at √s= 13 TeV | PRD 97 (2018) 092005 | CMS-EXO-16-048 1712.02345 |
53 | D. L. Rainwater, R. Szalapski, and D. Zeppenfeld | Probing color singlet exchange in Z + two jet events at the CERN LHC | PRD 54 (1996) 6680 | hep-ph/9605444 |
54 | CMS Collaboration | CMS luminosity measurement for the 2016 data-taking period | CMS-PAS-LUM-15-001 | CMS-PAS-LUM-15-001 |
55 | CMS Collaboration | CMS luminosity measurement for the 2017 data-taking period at √s= 13 TeV | CMS-PAS-LUM-17-004 | CMS-PAS-LUM-17-004 |
56 | CMS Collaboration | CMS luminosity measurement for the 2018 data-taking period at √s= 13 TeV | CMS-PAS-LUM-18-002 | CMS-PAS-LUM-18-002 |
57 | ATLAS Collaboration | Measurement of the inelastic proton-proton cross section at √s= 13 TeV with the ATLAS detector at the LHC | PRL 117 (2016) 182002 | 1606.02625 |
58 | CMS Collaboration | Measurement of the inelastic proton-proton cross section at √s= 13 TeV | JHEP 07 (2018) 161 | CMS-FSQ-15-005 1802.02613 |
59 | S. Catani, D. de Florian, M. Grazzini, and P. Nason | Soft gluon resummation for Higgs boson production at hadron colliders | JHEP 07 (2003) 028 | hep-ph/0306211 |
60 | M. Cacciari et al. | The tˉt cross section at 1.8 TeV and 1.96 TeV: a study of the systematics due to parton densities and scale dependence | JHEP 04 (2004) 068 | hep-ph/0303085 |
61 | J. Butterworth et al. | PDF4LHC recommendations for LHC run II | JPG 43 (2016) 023001 | 1510.03865 |
62 | A. L. Read | Presentation of search results: the CLs technique | JPG 28 (2002) 2693 | |
63 | T. Junk | Confidence level computation for combining searches with small statistics | NIMA 434 (1999) 435 | hep-ex/9902006 |
64 | The ATLAS Collaboration, The CMS Collaboration, The LHC Higgs Combination Group | Procedure for the LHC Higgs boson search combination in Summer 2011 | CMS-NOTE-2011-005 | |
65 | G. Cowan, K. Cranmer, E. Gross, and O. Vitells | Asymptotic formulae for likelihood-based tests of new physics | EPJC 71 (2011) 1554 | 1007.1727 |
![]() |
Compact Muon Solenoid LHC, CERN |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |