CMS logoCMS event Hgg
Compact Muon Solenoid
LHC, CERN

CMS-PAS-HIG-18-003
A search for pair production of new light bosons decaying into muons at $\sqrt{s}= $ 13 TeV
Abstract: This letter presents a search for new light bosons decaying into muon pairs using a data sample corresponding to an integrated luminosity of 35.9 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy $\sqrt{s} = $ 13 TeV collected with the CMS detector at the CERN LHC. The search is model independent, only requiring the pair production of a new light boson and its subsequent decay to a pair of muons. No significant deviation is observed from the predicted background and a model independent limit is set on the product of the cross section, branching ratio, and acceptance as a function of mass. This limit varies between 0.16 fb and 0.45 fb over a range of new light boson masses from 0.25 GeV to 8.5 GeV. It is then interpreted in the context of the Next-to-Minimal Supersymmetric Standard Model and a dark supersymmetry model that allows for non-negligible light boson lifetimes.
Figures & Tables Summary References CMS Publications
Figures

png pdf
Figure 1:
Left: The distribution of the invariant masses $m_{({\mu} {\mu})_1}$ vs. $m_{({\mu} {\mu})_2}$ for the isolated dimuon systems. There are 56 events in the data (bullets) that pass all selection criteria except for the $m_{({\mu} {\mu})_1} \simeq m_{({\mu} {\mu})_2}$ requirement and thus fall outside the diagonal region. The diagonal signal region $m_{({\mu} {\mu})_1} \simeq m_{({\mu} {\mu})_2}$ (outlined with dashed lines) contains the 13 events observed in data (triangles) that pass all selection criteria. The expected SM background distribution is indicated by the color scale. Right: The 95% CL upper limit set on ${\sigma ({\mathrm {p}} {\mathrm {p}}\to 2 \text {a} + \text {X}) \times \mathcal {B}^2 (\text {a} \rightarrow 2 {\mu}) \times \alpha _\text {Gen}}$ over the range 0.25 $ < m_{{\mathrm {a}}} < $ 8.5 GeV.

png pdf
Figure 1-a:
Left: The distribution of the invariant masses $m_{({\mu} {\mu})_1}$ vs. $m_{({\mu} {\mu})_2}$ for the isolated dimuon systems. There are 56 events in the data (bullets) that pass all selection criteria except for the $m_{({\mu} {\mu})_1} \simeq m_{({\mu} {\mu})_2}$ requirement and thus fall outside the diagonal region. The diagonal signal region $m_{({\mu} {\mu})_1} \simeq m_{({\mu} {\mu})_2}$ (outlined with dashed lines) contains the 13 events observed in data (triangles) that pass all selection criteria. The expected SM background distribution is indicated by the color scale. Right: The 95% CL upper limit set on ${\sigma ({\mathrm {p}} {\mathrm {p}}\to 2 \text {a} + \text {X}) \times \mathcal {B}^2 (\text {a} \rightarrow 2 {\mu}) \times \alpha _\text {Gen}}$ over the range 0.25 $ < m_{{\mathrm {a}}} < $ 8.5 GeV.

png pdf
Figure 1-b:
Left: The distribution of the invariant masses $m_{({\mu} {\mu})_1}$ vs. $m_{({\mu} {\mu})_2}$ for the isolated dimuon systems. There are 56 events in the data (bullets) that pass all selection criteria except for the $m_{({\mu} {\mu})_1} \simeq m_{({\mu} {\mu})_2}$ requirement and thus fall outside the diagonal region. The diagonal signal region $m_{({\mu} {\mu})_1} \simeq m_{({\mu} {\mu})_2}$ (outlined with dashed lines) contains the 13 events observed in data (triangles) that pass all selection criteria. The expected SM background distribution is indicated by the color scale. Right: The 95% CL upper limit set on ${\sigma ({\mathrm {p}} {\mathrm {p}}\to 2 \text {a} + \text {X}) \times \mathcal {B}^2 (\text {a} \rightarrow 2 {\mu}) \times \alpha _\text {Gen}}$ over the range 0.25 $ < m_{{\mathrm {a}}} < $ 8.5 GeV.

png pdf
Figure 2:
Left: The 95% CL upper limits in the NMSSM scenario as functions of ${m_{\text {h}_1}}$ on ${\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1,2} \to 2 \text {a}_1) \times \mathcal {B}^2(\text {a}_1 \to 2 {\mu})}$ with $m_{\text {a}_1} = $ 0.25 GeV (dashed curve) and $m_{\text {a}_1} = $ 3.55 GeV (dotted curve). The limits are compared to a representative predicted rate (solid curve) obtained using a simplified scenario where $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_1)=\sigma _\mathrm {SM}(m_{\text {h}_1})$ [60], ${\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_2) \times \mathcal {B}(\text {h}_{2} \rightarrow 2 \text {a}_1) = 0}$, $\mathcal {B}(\text {h}_1 \to 2 \text {a}_1) = 0.3%$, and $\mathcal {B}(\text {a}_1 \to 2 {\mu}) = 7.7%$. For the chosen $\mathcal {B}(\text {a}_1 \to 2 {\mu})$, taken from [46], $m_{\text {a}_1} = $ 2 GeV and NMSSM parameter $\tan\beta = 20$. The figure is separated into two regions: $m_{\text {h}_i}=m_{\text {h}_1} < 125 GeV $ with $m_{\text {h}_2}$ = 125 GeV (unshaded), and $m_{\text {h}_1}$ = 125 GeV with $m_{\text {h}_i}=m_{\text {h}_2} > 125 GeV $ (shaded). Right: The 95% CL upper limits as functions of $m_{\text {a}_1}$ in the NMSSM scenario on $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1,2} \to 2 \text {a}_1) \times \mathcal {B}^2(\text {a}_1 \to 2 {\mu})$ with $m_{\text {h}_1} = $ 90 GeV (dashed curve), $m_{\text {h}_1} = $ 125 GeV (dash-dotted curve), and $m_{\text {h}_1} = $ 150 GeV (dotted curve). These limits are compared to a representative predicted rate (solid curve) from a simplified case in which $\mathcal {B}(\text {h}_{1} \to 2 \text {a}_1) = 0.3%$, $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1})=\sigma _\mathrm {SM}(m_{\text {h}_{1}} = 125 GeV)$ [60], and $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_2) \times \mathcal {B}(\text {h}_{2} \rightarrow 2 \text {a}_1) = 0$. Additionally, $\mathcal {B}(\text {a}_1 \to 2 {\mu})$ as a function of $m_{\text {a}_1}$ is taken from [46] and assumes that the NMSSM parameter $\tan\beta $ is 20. The simplified scenario includes gg-fusion, VBF, and VH production modes. The structures in the predicted curves arise because $\mathcal {B}(\text {a}_1 \rightarrow gg)$ varies rapidly as $m_{\text {a}_1}$ crosses internal quark loop thresholds [46].

png pdf
Figure 2-a:
Left: The 95% CL upper limits in the NMSSM scenario as functions of ${m_{\text {h}_1}}$ on ${\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1,2} \to 2 \text {a}_1) \times \mathcal {B}^2(\text {a}_1 \to 2 {\mu})}$ with $m_{\text {a}_1} = $ 0.25 GeV (dashed curve) and $m_{\text {a}_1} = $ 3.55 GeV (dotted curve). The limits are compared to a representative predicted rate (solid curve) obtained using a simplified scenario where $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_1)=\sigma _\mathrm {SM}(m_{\text {h}_1})$ [60], ${\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_2) \times \mathcal {B}(\text {h}_{2} \rightarrow 2 \text {a}_1) = 0}$, $\mathcal {B}(\text {h}_1 \to 2 \text {a}_1) = 0.3%$, and $\mathcal {B}(\text {a}_1 \to 2 {\mu}) = 7.7%$. For the chosen $\mathcal {B}(\text {a}_1 \to 2 {\mu})$, taken from [46], $m_{\text {a}_1} = $ 2 GeV and NMSSM parameter $\tan\beta = 20$. The figure is separated into two regions: $m_{\text {h}_i}=m_{\text {h}_1} < 125 GeV $ with $m_{\text {h}_2}$ = 125 GeV (unshaded), and $m_{\text {h}_1}$ = 125 GeV with $m_{\text {h}_i}=m_{\text {h}_2} > 125 GeV $ (shaded). Right: The 95% CL upper limits as functions of $m_{\text {a}_1}$ in the NMSSM scenario on $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1,2} \to 2 \text {a}_1) \times \mathcal {B}^2(\text {a}_1 \to 2 {\mu})$ with $m_{\text {h}_1} = $ 90 GeV (dashed curve), $m_{\text {h}_1} = $ 125 GeV (dash-dotted curve), and $m_{\text {h}_1} = $ 150 GeV (dotted curve). These limits are compared to a representative predicted rate (solid curve) from a simplified case in which $\mathcal {B}(\text {h}_{1} \to 2 \text {a}_1) = 0.3%$, $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1})=\sigma _\mathrm {SM}(m_{\text {h}_{1}} = 125 GeV)$ [60], and $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_2) \times \mathcal {B}(\text {h}_{2} \rightarrow 2 \text {a}_1) = 0$. Additionally, $\mathcal {B}(\text {a}_1 \to 2 {\mu})$ as a function of $m_{\text {a}_1}$ is taken from [46] and assumes that the NMSSM parameter $\tan\beta $ is 20. The simplified scenario includes gg-fusion, VBF, and VH production modes. The structures in the predicted curves arise because $\mathcal {B}(\text {a}_1 \rightarrow gg)$ varies rapidly as $m_{\text {a}_1}$ crosses internal quark loop thresholds [46].

png pdf
Figure 2-b:
Left: The 95% CL upper limits in the NMSSM scenario as functions of ${m_{\text {h}_1}}$ on ${\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1,2} \to 2 \text {a}_1) \times \mathcal {B}^2(\text {a}_1 \to 2 {\mu})}$ with $m_{\text {a}_1} = $ 0.25 GeV (dashed curve) and $m_{\text {a}_1} = $ 3.55 GeV (dotted curve). The limits are compared to a representative predicted rate (solid curve) obtained using a simplified scenario where $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_1)=\sigma _\mathrm {SM}(m_{\text {h}_1})$ [60], ${\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_2) \times \mathcal {B}(\text {h}_{2} \rightarrow 2 \text {a}_1) = 0}$, $\mathcal {B}(\text {h}_1 \to 2 \text {a}_1) = 0.3%$, and $\mathcal {B}(\text {a}_1 \to 2 {\mu}) = 7.7%$. For the chosen $\mathcal {B}(\text {a}_1 \to 2 {\mu})$, taken from [46], $m_{\text {a}_1} = $ 2 GeV and NMSSM parameter $\tan\beta = 20$. The figure is separated into two regions: $m_{\text {h}_i}=m_{\text {h}_1} < 125 GeV $ with $m_{\text {h}_2}$ = 125 GeV (unshaded), and $m_{\text {h}_1}$ = 125 GeV with $m_{\text {h}_i}=m_{\text {h}_2} > 125 GeV $ (shaded). Right: The 95% CL upper limits as functions of $m_{\text {a}_1}$ in the NMSSM scenario on $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1,2} \to 2 \text {a}_1) \times \mathcal {B}^2(\text {a}_1 \to 2 {\mu})$ with $m_{\text {h}_1} = $ 90 GeV (dashed curve), $m_{\text {h}_1} = $ 125 GeV (dash-dotted curve), and $m_{\text {h}_1} = $ 150 GeV (dotted curve). These limits are compared to a representative predicted rate (solid curve) from a simplified case in which $\mathcal {B}(\text {h}_{1} \to 2 \text {a}_1) = 0.3%$, $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_{1})=\sigma _\mathrm {SM}(m_{\text {h}_{1}} = 125 GeV)$ [60], and $\sigma ({\mathrm {p}} {\mathrm {p}}\to \text {h}_2) \times \mathcal {B}(\text {h}_{2} \rightarrow 2 \text {a}_1) = 0$. Additionally, $\mathcal {B}(\text {a}_1 \to 2 {\mu})$ as a function of $m_{\text {a}_1}$ is taken from [46] and assumes that the NMSSM parameter $\tan\beta $ is 20. The simplified scenario includes gg-fusion, VBF, and VH production modes. The structures in the predicted curves arise because $\mathcal {B}(\text {a}_1 \rightarrow gg)$ varies rapidly as $m_{\text {a}_1}$ crosses internal quark loop thresholds [46].

png pdf
Figure 3:
The 90% CL upper limits (black solid curves) from this search as interpreted in the dark SUSY scenario, where $\sigma ({\mathrm {p}} {\mathrm {p}}\to {\mathrm {h}} +\mathrm{X}) \, \mathcal {B}({\mathrm {h}} \to 2{{\gamma}}_{D} + \mathrm{X})$ with $m_{\mathrm {n}_1}=$ 10 GeV, $m_{\mathrm {n}_{\mathrm {D}}}=$ 1 GeV. The limits are presented in the plane of the parameters ($\varepsilon $ and $m_{{{\gamma}}_{D}}$). Constraints from other experiments [21,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75] showing their 90% CL exclusion contours are also shown. The colored contours for the CMS and ATLAS limits represent different values of $\mathcal {B}({\mathrm {h}} \to 2{{\gamma}}_{D} + \mathrm{X})$ that range from 0.1 to 40%.
Tables

png pdf
Table 1:
The full reconstruction efficiency over signal acceptance $\epsilon _\mathrm {Full}/\alpha _\mathrm {Gen}$ in% for several representative signal NMSSM (top) and dark SUSY benchmark models (bottom).
Summary
A search for pairs of new light bosons that subsequently decay to pairs of oppositely charged muons is presented in this Letter. This search is developed in the context of a Higgs boson decay, $\mathrm{h} \rightarrow 2\mathrm{A}+\mathrm{X}\rightarrow 4\mu+\mathrm{X}$ and is performed on a data sample collected by the CMS experiment in 2016 that corresponds to an integrated luminosity of 35.9 fb$^{-1}$ proton-proton collisions with $\sqrt{s}= $ 13 TeV. This dataset is larger and collected at a higher center-of-mass energy than the previous version of this search [15]. Additionally, both the mass range of the a boson and the maximum possible displacement of its decay vertex are extended compared to the previous publication of this analysis. Thirteen events are observed in the signal region, with 9.90 $\pm$ 1.24 (stat) $\pm$ 1.84 (syst) events expected from the SM backgrounds. The distribution of events in the signal region is consistent with SM expectations. A model independent 95% CL upper limit on the product of the cross section, branching fraction, and acceptance is set over the mass range 0.25 $ < m_{\mathrm{A}} < $ 8.5 GeV. This model independent limit is then interpreted in the context of dark SUSY with non-negligible light boson lifetime and the NMSSM. In the dark SUSY interpretation of the result, the new limit constrains previously unexamined ranges of $\varepsilon$ and $m_{\gamma_D}$.
References
1 M. Maniatis The next-to-minimal supersymmetric extension of the standard model reviewed Int. J. Mod. Phys. A 25 (2010) 3505 0906.0777
2 L. D. Duffy and K. van Bibber Axions as dark matter particles New J. Phys 11 (2009) 105008 hep-ph/0904.3346
3 N. Arkani-Hamed, D. P. Finkbeiner, T. R. Slatyer, and N. Weiner A theory of dark matter PRD 79 (2009) 015014 0810.0713
4 A. Belyaev et al. LHC discovery potential of the lightest NMSSM Higgs boson in the $ {h}_{1} {\rightarrow}{a}_{1}{a}_{1} {\rightarrow}4 {\mu} $ channel PRD 81 (2010) 075021 hep-ph/1002.1956
5 P. Fayet Supergauge invariant extension of the Higgs mechanism and a model for the electron and its neutrino NPB 90 (1975) 104
6 R. K. Kaul and P. Majumdar Cancellation of quadratically divergent mass corrections in globally supersymmetric spontaneously broken gauge theories NPB 199 (1982) 36
7 R. Barbieri, S. Ferrara, and C. A. Savoy Gauge models with spontaneously broken local supersymmetry PLB 119 (1982) 343
8 H. P. Nilles, M. Srednicki, and D. Wyler Weak interaction breakdown induced by supergravity PL120 (1983) 346
9 J.-M. Frere, D. R. T. Jones, and S. Raby Fermion masses and induction of the weak scale by supergravity NPB 222 (1983) 11
10 J.-P. Derendinger and C. A. Savoy Quantum effects and SU(2)$ \times $U(1) breaking in supergravity gauge theories NPB 237 (1984) 307
11 M. Drees Supersymmetric models with extended Higgs sector Int. J. Mod. Phys. A 4 (1989) 3635
12 U. Ellwanger, C. Hugonie, and A. M. Teixeira The next-to-minimal supersymmetric standard model PR 496 (2010) 1 0910.1785
13 M. Baumgart et al. Non-abelian dark sectors and their collider signatures JHEP 04 (2009) 014 0901.0283
14 A. Falkowski, J. T. Ruderman, T. Volansky, and J. Zupan Hidden Higgs decaying to lepton jets JHEP 05 (2010) 077 1002.2952
15 CMS Collaboration A search for pair production of new light bosons decaying into muons PLB 752 (2016) 146 CMS-HIG-13-010
1506.00424
16 ATLAS Collaboration Search for displaced muonic lepton jets from light Higgs boson decay in proton-proton collisions $ \sqrt{s}= $ 7 TeV with the ATLAS detector PLB 721 (2013) 32 1210.0435
17 CMS Collaboration Search for light resonances decaying into pairs of muons as a signal of new physics JHEP 07 (2011) 98 CMS-EXO-11-013
1106.2375
18 CMS Collaboration Search for a very light NMSSM Higgs boson produced in decays of the 125 GeV scalar boson and decaying into $ \tau $ leptons in pp collisions at $ \sqrt{s}= $ 8 TeV JHEP 01 (2016) 079 CMS-HIG-14-019
1510.06534
19 ATLAS Collaboration Search for new light gauge bosons in Higgs boson decays to four-lepton final states in pp collisions at $ \sqrt{s}= $ 8 TeV with the ATLAS detector at the LHC PRD 92 (2015) 092001 1505.07645
20 ATLAS Collaboration Search for Higgs boson decays to beyond-the-Standard-Model light bosons in four-lepton events with the ATLAS detector at $ \sqrt{s}= $ 13 TeV Submitted to \it JHEP 1802.03388
21 ATLAS Collaboration Search for long-lived neutral particles decaying into lepton jets in proton--proton collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector JHEP 11 (2014) 88 1409.0746
22 ATLAS Collaboration Search for the Higgs boson produced in association with a W boson and decaying to four b-quarks via two spin-zero particles in pp collisions at 13 TeV with the ATLAS detector EPJC 76 (2016) 605 1606.08391
23 ATLAS Collaboration Search for the Higgs boson produced in association with a vector boson and decaying into two spin-zero particles in the $ H \rightarrow aa \rightarrow 4b $ channel in $ pp $ collisions at $ \sqrt{s} = $ 13 TeV with the ATLAS detector Submitted to \it JHEP 1806.07355
24 ATLAS Collaboration Search for new phenomena in events with at least three photons collected in pp collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector EPJC 76 (2016) 210 1509.05051
25 CMS Collaboration Search for the exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two b quarks and two $ \tau $ leptons Submitted to \it PLB CMS-HIG-17-024
1805.10191
26 CMS Collaboration Search for the exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state of two muons and two $ \tau $ leptons at $ \sqrt{s}= $ 13 TeV Submitted to \it JHEP CMS-HIG-17-029
1805.04865
27 LHCb Collaboration Search for Higgs-like bosons decaying into long-lived exotic particles The EPJC 76 (2016) 664 1609.03124
28 CMS Collaboration Search for a non-standard-model Higgs boson decaying to a pair of new light bosons in four-muon final states PLB 726 (2013) 564 CMS-EXO-12-012
1210.7619
29 CMS Collaboration Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s} = $ 13 TeV Submitted to \it JINST CMS-MUO-16-001
1804.04528
30 CMS Collaboration Performance of CMS muon reconstruction in $ pp $ collision events at $ \sqrt{s} = $ 7 TeV JINST 7 (2012) P10002 CMS-MUO-10-004
1206.4071
31 CMS Collaboration The CMS trigger system JINST 12 (2017) P01020 CMS-TRG-12-001
1609.02366
32 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004 CMS-00-001
33 CMS Collaboration Particle-flow reconstruction and global event description with the CMS detector JINST 12 (2017) P10003 CMS-PRF-14-001
1706.04965
34 W. Adam, B. Mangano, T. Speer, and T. Todorov Track reconstruction in the CMS tracker CMS-NOTE-2006-041
35 NNPDF Collaboration Parton distributions with QED corrections NPB 877 (2013) 290--320 1308.0598
36 T. Sjostrand et al. An introduction to PYTHIA 8.2 Computer Physics Communications 191 (2015) 159 1410.3012
37 P. Skands, S. Carrazza, and J. Rojo Tuning PYTHIA 8.1: the Monash 2013 tune EPJC 74 (2014) 3024 1404.5630
38 WMAP Collaboration Nine-year Wilkinson microwave anisotropy probe (WMAP) observations: Cosmological parameter results Astrophys. J. Suppl. 208 (2013) 19 1212.5226
39 Planck Collaboration Planck 2013 results. XVI. Cosmological parameters Astron. Astrophys. 571 (2014) A16 1303.5076
40 OPAL Collaboration Decay mode independent searches for new scalar bosons with the OPAL detector at LEP EPJC 27 (2003) 311 hep-ex/0206022
41 OPAL Collaboration Search for a low mass CP-odd Higgs boson in $ \mathrm{e^{+}}\mathrm{e^{-}} $ collisions with the OPAL detector at LEP-2 EPJC 27 (2003) 483 hep-ex/0209068
42 ALEPH, DELPHI, L3, OPAL, LEP Working Group for Higgs Boson Searches Collaboration Search for neutral MSSM Higgs bosons at LEP EPJC 47 (2006) 547 hep-ex/0602042
43 OPAL Collaboration Search for neutral Higgs boson in CP-conserving and CP-violating MSSM scenarios EPJC 37 (2004) 49 hep-ex/0406057
44 DELPHI Collaboration Searches for neutral Higgs bosons in extended models EPJC 38 (2004) 1 hep-ex/0410017
45 ALEPH Collaboration Search for neutral Higgs bosons decaying into four taus at LEP2 JHEP 05 (2010) 049 1003.0705
46 R. Dermisek and J. F. Gunion New constraints on a light CP-odd Higgs boson and related NMSSM ideal Higgs scenarios PRD 81 (2010) 075003 1002.1971
47 J. Alwall et al. MadGraph/MadEvent v4: the new web generation JHEP 09 (2007) 028 0706.2334
48 P. Meade and M. Reece BRIDGE: Branching ratio inquiry / decay generated events hep-ph/0703031
49 GEANT4 Collaboration GEANT4---a simulation toolkit NIMA 506 (2003) 250
50 CMS Collaboration Search for supersymmetry in pp collisions at $ \sqrt{s}= $ 13 TeV in the single-lepton final state using the sum of masses of large-radius jets JHEP 08 (2016) 122 1605.04608v2
51 T. Sjostrand, S. Mrenna, and P. Z. Skands A brief introduction to PYTHIA 8.1 CPC 178 (2008) 852 0710.3820
52 M. Bahr et al. Herwig++ physics and manual EPJC 58 (2008) 639 0803.0883
53 A. Belyaev, N. D. Christensen, and A. Pukhov CalcHEP 3.4 for collider physics within and beyond the standard model CPC 184 (2013) 1729 1207.6082
54 CMS Collaboration CMS luminosity measurements for the 2016 data taking period CMS-PAS-LUM-17-001 CMS-PAS-LUM-17-001
55 M. Botje et al. The PDF4LHC working group interim recommendations 1101.0538
56 S. Alekhin et al. The PDF4LHC working group interim report 1101.0536
57 R. D. Ball et al. Parton distributions with LHC data NPB 867 (2013) 244 1207.1303
58 J. Butterworth et al. PDF4LHC recommendations for LHC Run II JPG: Nucl. Part. Phys. 43 (2016) 023001 1510.03865v2
59 J. M. Campbell and R. Ellis Loops and legs in quantum field theory MCFM for the Tevatron and the LHC NPB Proc. Suppl. 205 (2010) 10 1007.3492v1
60 LHC Higgs Cross Section Working Group Collaboration Handbook of LHC Higgs cross sections: 1. inclusive observables 1101.0593
61 PHENIX Collaboration Search for dark photons from neutral meson decays in $ p+p $ and $ d+\mathrm{Au} $ collisions at $ \sqrt{{s}_{NN}}= $ 200 GeV PRC 91 (2015) 031901 1409.0851
62 KLOE-2 Collaboration Search for light vector boson production in $ e^+e^-\rightarrow \mu^+ \mu^-\gamma $ interactions with the KLOE experiment PLB 736 (2014) 459 1404.7772
63 APEX Collaboration Search for a new gauge boson in electron-nucleus fixed-target scattering by the APEX Experiment PRL 107 (2011) 191804 1108.2750
64 A. Adare et al. Search at the Mainz Microtron for light massive gauge bosons relevant for the muon g-2 anomaly PRL 112 (2014) 221802 1404.5502
65 HADES Collaboration Searching a dark photon with HADES PLB 731 (2014) 265 1311.0216
66 BaBar Collaboration Search for a dark photon in e+e- collisions at BABAR PRL 113 (2014) 201801 1406.2980
67 A. Fradette, M. Pospelov, J. Pradler, and A. Ritz Cosmological constraints on very dark photons PRD 90 (2014) 035022 1407.0993
68 R. Essig et al. Working group report: New light weakly coupled particles 1311.0029
69 L. M. K. James B. Dent, Francesc Ferrer Constraints on light hidden sector gauge bosons from supernova cooling 1201.2683
70 H. K. Dreiner, J. Fortin, and L. U. C. Hanhart Supernova constraints on MeV dark sectors from e+ e- annihilations PRD 89 (2014) 105015 1310.3826
71 J. B. J. Blumlein New exclusion limits for dark gauge forces from beam-dump data PLB 701 (2011) 155 1104.2747
72 R. Essig, R. Harnik, J. Kaplan, and N. Toro Discovering new light states at neutrino experiments PRD 82 (2010) 113008 1008.0636
73 A. R. Brian Batell, Maxim Pospelov Exploring portals to a hidden sector through fixed targets PRD 80 (2009) 095024 0906.5614
74 S. N. Gninenko Constraints on sub-GeV hidden sector gauge bosons from a search for heavy neutrino decays PLB 713 (2012) 244 1204.3583
75 LHCb Collaboration Search for dark photons produced in 13 TeV pp collisions PRL 120 (2018) 061801 1710.02867
76 B. Batell, M. Pospelov, and A. Ritz Probing a secluded U(1) at B-factories PRD 79 (2009) 115008 0903.0363
Compact Muon Solenoid
LHC, CERN