Publications by Jan Steggemann

Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Rakesh Chawla, Yixing Chen, Chunhui Chen, Tian Cheng, Pratyush Das, João Miguel das Neves Duarte, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Bertrand François, Sebastiana Gianì, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Muhammad Ansar Iqbal, Alexis Kalogeropoulos, Viktor Khristenko, Doohyun Kim, Donghyun Kim, Ji Hyun Kim, Sanjeev Kumar, Ajay Kumar, Vineet Kumar, Ekaterina Kuznetsova, Federica Legger, Yiming Li, Jing Li, Zhen Liu, Werner Lustermann, Maren Tabea Meinhard, Ioannis Papadopoulos, Anton Petrov, Vladimir Petrov, Jessica Prisciandaro, Quentin Python, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Arvind Shah, Varun Sharma, Ashish Sharma, Wei Shi, Kun Shi, Muhammad Shoaib, Bandeep Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, David Vannerom, Joao Varela, Zheng Wang, Jian Wang, Xiao Wang, Hui Wang, Qian Wang, Yi Wang, Siyuan Wang, Matthias Weber, Matthias Wolf, Meng Xiao, Yong Yang, Kai Yi, Yi Zhang, Hua Zhang, Jian Zhao

The performance is presented of the reconstruction and identification algorithms for electrons and photons with the CMS experiment at the LHC. The reported results are based on proton-proton collision data collected at a center-of-mass energy of 13 TeV and recorded in 2016-2018, corresponding to an integrated luminosity of 136 fb(-1). Results obtained from lead-lead collision data collected at root S-NN = 5.02 TeV are also presented. Innovative techniques are used to reconstruct the electron and photon signals in the detector and to optimize the energy resolution. Events with electrons and photons in the final state are used to measure the energy resolution and energy scale uncertainty in the recorded events. The measured energy resolution for electrons produced in Z boson decays in proton-proton collision data ranges from 2 to 5%, depending on electron pseudorapidity and energy loss through bremsstrahlung in the detector material. The energy scale in the same range of energies is measured with an uncertainty smaller than 0.1 (0.3)% in the barrel (endcap) region in proton-proton collisions and better than 1(3)% in the barrel (endcap) region in heavy ion collisions. The timing resolution for electrons from Z boson decays with the full 2016-2018 proton-proton collision data set is measured to be 200 ps.

2021

Measurement of the W gamma Production Cross Section in Proton-Proton Collisions at root s=13 TeV and Constraints on Effective Field Theory Coefficients

Muhammad Ahmad, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Rakesh Chawla, Chunhui Chen, Yixing Chen, Tian Cheng, Pratyush Das, João Miguel das Neves Duarte, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Bertrand François, Sebastiana Gianì, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Muhammad Ansar Iqbal, Alexis Kalogeropoulos, Viktor Khristenko, Doohyun Kim, Donghyun Kim, Ji Hyun Kim, Sanjeev Kumar, Ajay Kumar, Vineet Kumar, Ekaterina Kuznetsova, Federica Legger, Jing Li, Yiming Li, Zhen Liu, Werner Lustermann, Maren Tabea Meinhard, Ioannis Papadopoulos, Anton Petrov, Vladimir Petrov, Jessica Prisciandaro, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Arvind Shah, Varun Sharma, Ashish Sharma, Wei Shi, Kun Shi, Bandeep Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, David Vannerom, Joao Varela, Xiao Wang, Siyuan Wang, Yi Wang, Hui Wang, Jian Wang, Zheng Wang, Qian Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Meng Xiao, Yong Yang, Kai Yi, Yi Zhang, Hua Zhang, Jian Zhao

A fiducial cross section for W gamma production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in 137 fb(-1) of data collected using the CMS detector at the LHC. The W -> e nu and mu nu decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.

2021

Observation of a New Excited Beauty Strange Baryon Decaying to Xi(-)(b)pi(+)pi(-)

Muhammad Ahmad, Georgios Anagnostou, Guido Andreassi, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Rakesh Chawla, Chunhui Chen, Yixing Chen, Tian Cheng, Pratyush Das, João Miguel das Neves Duarte, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Sebastiana Gianì, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Miao Hu, Muhammad Ansar Iqbal, Alexis Kalogeropoulos, Viktor Khristenko, Donghyun Kim, Doohyun Kim, Ji Hyun Kim, Ajay Kumar, Mithlesh Kumar, Vineet Kumar, Sanjeev Kumar, Ekaterina Kuznetsova, Federica Legger, Yiming Li, Jing Li, Zhen Liu, Werner Lustermann, Maren Tabea Meinhard, Ioannis Papadopoulos, Anton Petrov, Vladimir Petrov, Marco Pisano, Jessica Prisciandaro, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Arvind Shah, Varun Sharma, Ashish Sharma, Wei Shi, Kun Shi, Muhammad Shoaib, Bandeep Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, David Vannerom, Joao Varela, Yi Wang, Jian Wang, Xiao Wang, Hui Wang, Zheng Wang, Qian Wang, Siyuan Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Meng Xiao, Yong Yang, Kai Yi, Hua Zhang, Yi Zhang, Jian Zhao

The Xi(-)(b)pi(+)pi(-) invariant mass spectrum is investigated with an event sample of proton-proton collisions at root s = 13 TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140 fb(-1). The ground state Xi(-)(b) is reconstructed via its decays to J/psi Xi(-) and J/psi Lambda K-. A narrow resonance, labeled Xi(b)(6100)(-), is observed at a Xi(-)(b)pi(+)pi(-) invariant mass of 6100.3 +/- 0.2(stat) +/- 0.1(syst) +/- 0.6(Xi(-)(b)) MeV, where the last uncertainty reflects the precision of the Xi(-)(b) baryon mass. The upper limit on the Xi(b)(6100)(-) natural width is determined to be 1.9 MeV at 95% confidence level. The low Xi(b)(6100)(-) signal yield observed in data does not allow a measurement of the quantum numbers of the new state. However, following analogies with the established excited Xi(c) baryon states, the new Xi(b)(6100)(-) resonance and its decay sequence are consistent with the orbitally excited Xi(- )(b)baryon, with spin and parity quantum numbers J(P) = 3/2(-).

2021

Search for singly and pair-produced leptoquarks coupling to third-generation fermions in proton-proton collisions at root s=13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Rakesh Chawla, Chunhui Chen, Yixing Chen, Tian Cheng, Pratyush Das, João Miguel das Neves Duarte, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Bertrand François, Sebastiana Gianì, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Muhammad Ansar Iqbal, Alexis Kalogeropoulos, Viktor Khristenko, Doohyun Kim, Ji Hyun Kim, Donghyun Kim, Ajay Kumar, Sanjeev Kumar, Vineet Kumar, Ekaterina Kuznetsova, Federica Legger, Jing Li, Yiming Li, Zhen Liu, Werner Lustermann, Maren Tabea Meinhard, Ioannis Papadopoulos, Anton Petrov, Vladimir Petrov, Jessica Prisciandaro, Quentin Python, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Arvind Shah, Ashish Sharma, Varun Sharma, Wei Shi, Kun Shi, Muhammad Shoaib, Bandeep Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, David Vannerom, Joao Varela, Zheng Wang, Xiao Wang, Hui Wang, Qian Wang, Siyuan Wang, Jian Wang, Yi Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Yong Yang, Kai Yi, Yi Zhang, Hua Zhang, Jian Zhao

A search for leptoquarks produced singly and in pairs in proton-proton collisions is presented. We consider the leptoquark (LQ) to be a scalar particle of charge -1/3e coupling to a top quark plus a tau lepton (t tau) or a bottom quark plus a neutrino (b nu), or a vector particle of charge +2/3e, coupling to t nu or b tau. These choices are motivated by models that can explain a series of anomalies observed in the measurement of B meson decays. In this analysis the signatures t tau nu b and t tau nu are probed, using data recorded by the CMS experiment at the CERN LHC at root s = 13 TeV and that correspond to an integrated luminosity of 137 fb(-1). These signatures have not been previously explored in a dedicated search. The data are found to be in agreement with the standard model prediction. Lower limits at 95% confidence level are set on the LQ mass in the range 0.98-1.73 TeV, depending on the LQ spin and its coupling lambda to a lepton and a quark, and assuming equal couplings for the two LQ decay modes considered. These are the most stringent constraints to date on the existence of leptoquarks in this scenario. (C) 2021 The Author(s). Published by Elsevier B.V.

2021

Search for the rare decay of the W boson into a pion and a photon in proton-proton collisions at root s=13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Rakesh Chawla, Chunhui Chen, Yixing Chen, Tian Cheng, Pratyush Das, João Miguel das Neves Duarte, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Bertrand François, Sebastiana Gianì, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Muhammad Ansar Iqbal, Alexis Kalogeropoulos, Viktor Khristenko, Doohyun Kim, Ji Hyun Kim, Donghyun Kim, Ajay Kumar, Sanjeev Kumar, Vineet Kumar, Ekaterina Kuznetsova, Federica Legger, Jing Li, Yiming Li, Zhen Liu, Werner Lustermann, Maren Tabea Meinhard, Ioannis Papadopoulos, Anton Petrov, Vladimir Petrov, Jessica Prisciandaro, Quentin Python, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Arvind Shah, Ashish Sharma, Varun Sharma, Wei Shi, Kun Shi, Muhammad Shoaib, Bandeep Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, David Vannerom, Joao Varela, Zheng Wang, Xiao Wang, Hui Wang, Qian Wang, Siyuan Wang, Jian Wang, Yi Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Yong Yang, Kai Yi, Yi Zhang, Hua Zhang, Jian Zhao

A search is performed for the rare decay W-+/--> pi(+/-)gamma in proton-proton collisions at root s = 13 TeV. Data corresponding to an integrated luminosity of 137 fb(-1) were collected during 2016 to 2018 with the CMS detector. This analysis exploits a novel search strategy based on W boson production in top quark pair events. An inclusive search for the W-+/--> pi(+/-)gamma decay is not optimal at the LHC because of the high trigger thresholds. Instead, a trigger selection is exploited in which the W boson originating from one of the top quarks is used to tag the event in a leptonic decay. The W boson emerging from the other top quark is used to search for the W-+/--> pi(+/-)gamma signature. Such decays are characterized by an isolated track pointing to a large energy deposit, and by an isolated photon of large transverse momentum. The presence of b quark jets reduces the background from the hadronization of light-flavor quarks and gluons. The W-+/- -> pi(+/-)gamma decay is not observed. An upper exclusion limit is set to this branching fraction, corresponding to 1.50 x 10(-5) at 95% confidence level, whereas the expected upper exclusion limit is 0.85(-0.29)(+0.52) x 10(-5). (C) 2021 The Author(s). Published by Elsevier B.V.

2021

Search for top squark production in fully hadronic final states in proton-proton collisions at root s=13 TeV

Muhammad Ahmad, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Rakesh Chawla, Chunhui Chen, Yixing Chen, Tian Cheng, Pratyush Das, João Miguel das Neves Duarte, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Bertrand François, Sebastiana Gianì, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Muhammad Ansar Iqbal, Alexis Kalogeropoulos, Viktor Khristenko, Doohyun Kim, Donghyun Kim, Ji Hyun Kim, Sanjeev Kumar, Ajay Kumar, Vineet Kumar, Ekaterina Kuznetsova, Federica Legger, Jing Li, Yiming Li, Zhen Liu, Werner Lustermann, Maren Tabea Meinhard, Ioannis Papadopoulos, Anton Petrov, Vladimir Petrov, Jessica Prisciandaro, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Arvind Shah, Varun Sharma, Ashish Sharma, Wei Shi, Kun Shi, Muhammad Shoaib, Bandeep Singh, Jan Steggemann, Wei Sun, Andromachi Tsirou, David Vannerom, Joao Varela, Yi Wang, Zheng Wang, Xiao Wang, Hui Wang, Jian Wang, Qian Wang, Siyuan Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Meng Xiao, Yong Yang, Kai Yi, Hua Zhang, Yi Zhang, Jian Zhao

A search for production of the supersymmetric partners of the top quark, top squarks, is presented. The search is based on proton-proton collision events containing multiple jets, no leptons, and large transverse momentum imbalance. The data were collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 137 fb(-1). The targeted signal production scenarios are direct and gluino-mediated top squark production, including scenarios in which the top squark and neutralino masses are nearly degenerate. The search utilizes novel algorithms based on deep neural networks that identify hadronically decaying top quarks and W bosons, which are expected in many of the targeted signal models. No statistically significant excess of events is observed relative to the expectation from the standard model, and limits on the top squark production cross section are obtained in the context of simplified supersymmetric models for various production and decay modes. Exclusion limits as high as 1310 GeVare established at the 95% confidence level on the mass of the top squark for direct top squark production models, and as high as 2260 GeV on the mass of the gluino for gluino-mediated top squark production models. These results represent a significant improvement over the results of previous searches for supersymmetry by CMS in the same final state.

2021

Extended Scalar Sectors

Jan Steggemann

Extended scalar sectors appear in various extensions of the Standard Model of particle physics, such as supersymmetric models. They are also generic extensions of the Standard Model and can address a number of its shortcomings. Direct searches for additional Higgs bosons and measurements of the 125-GeV Higgs boson, both of which provide insights into the different possible sectors, are carried out at the LHC. This review gives an overview of searches for the additional Higgs bosons and their implications for different models. The discussed analyses comprise searches for neutral and charged Higgs bosons that decay in various final states. In addition, the review summarizes the constraints from precision measurements, including in particular the observed couplings of the 125-GeV Higgs boson. While several models naturally incorporate a Higgs boson with couplings that are similar to the ones in the Standard Model, the measurements of the 125-GeV Higgs boson provide constraints on all considered extensions.

ANNUAL REVIEWS2020

Search for light pseudoscalar boson pairs produced from decays of the 125 GeV Higgs boson in final states with two muons and two nearby tracks in pp collisions at $\sqrt{s}=$ 13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Xin Chen, Yixing Chen, Tian Cheng, Davide Cieri, Giuseppe Codispoti, Pratyush Das, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Daniel Gonzalez, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Alexis Kalogeropoulos, Viktor Khristenko, Ji Hyun Kim, Donghyun Kim, Ajay Kumar, Sanjeev Kumar, Vineet Kumar, Ekaterina Kuznetsova, Jing Li, Lei Li, Wei Li, Ho Ling Li, Zhen Liu, Hao Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Quentin Python, Andrea Rizzi, Paolo Ronchese, Sourav Sen, Ashish Sharma, Varun Sharma, Lesya Shchutska, Kun Shi, Wei Shi, Muhammad Shoaib, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Siyuan Wang, Zheng Wang, Mingkui Wang, Xiao Wang, Hui Wang, Jian Wang, Qian Wang, Yi Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Yong Yang

A search is presented for pairs of light pseudoscalar bosons, in the mass range from 4 to 15 GeV, produced from decays of the 125 GeV Higgs boson. The decay modes considered are final states that arise when one of the pseudoscalars decays to a pair of tau leptons, and the other one either into a pair of tau leptons or muons. The search is based on proton-proton collisions collected by the CMS experiment in 2016 at a center-of-mass energy of 13 TeV that correspond to an integrated luminosity of 35.9 fb−1 . The 2μ2τ and 4 τ channels are used in combination to constrain the product of the Higgs boson production cross section and the branching fraction into 4 τ final state, σB , exploiting the linear dependence of the fermionic coupling strength of pseudoscalar bosons on the fermion mass. No significant excess is observed beyond the expectation from the standard model. The observed and expected upper limits at 95% confidence level on σB , relative to the standard model Higgs boson production cross section, are set respectively between 0.022 and 0.23 and between 0.027 and 0.19 in the mass range probed by the analysis.

2020

A multi-dimensional search for new heavy resonances decaying to boosted WW, WZ, or ZZ boson pairs in the dijet final state at 13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Thomas Berger, Michele Bianco, Alessandro Caratelli, Xin Chen, Tian Cheng, Davide Cieri, Giuseppe Codispoti, Pratyush Das, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Sebastiana Gianì, Daniel Gonzalez, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Alexis Kalogeropoulos, Viktor Khristenko, Ji Hyun Kim, Donghyun Kim, Vineet Kumar, Ajay Kumar, Sanjeev Kumar, Ekaterina Kuznetsova, Wei Li, Lei Li, Jing Li, Yiming Li, Zhen Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Amr Mohamed, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Jessica Prisciandaro, Quentin Python, Andrea Rizzi, Paolo Ronchese, Valérie Scheurer, Sourav Sen, Ashish Sharma, Varun Sharma, Lesya Shchutska, Wei Shi, Kun Shi, Muhammad Shoaib, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Mingkui Wang, Yi Wang, Qian Wang, Zheng Wang, Jian Wang, Siyuan Wang, Xiao Wang, Hui Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Yong Yang, Yi Zhang

A search in an all-jet final state for new massive resonances decaying to WW, WZ, or ZZ boson pairs using a novel analysis method is presented. The analysis is performed on data corresponding to an integrated luminosity of 77.3 fb

^{-1}

recorded with the CMS experiment at the LHC at a centre-of-mass energy of 13 TeV. The search is focussed on potential resonances with masses above 1.2 TeV, where the decay products of each W or Z boson are expected to be collimated into a single, large-radius jet. The signal is extracted using a three-dimensional maximum likelihood fit of the two jet masses and the dijet invariant mass, yielding an improvement in sensitivity of up to 30% relative to previous search methods. No excess is observed above the estimated standard model background. In a heavy vector triplet model, spin-1 Z' and W' resonances with masses below 3.5 and 3.8 TeV, respectively, are excluded at 95% confidence level. In a narrow-width bulk graviton model, upper limits on cross sections are set between 27 and 0.2 fb for resonance masses between 1.2 and 5.2 TeV, respectively. The limits presented in this paper are the best to date in the dijet final state.

2019

A search for pair production of new light bosons decaying into muons in proton-proton collisions at 13 TeV

Muhammad Ahmad, Benjamin William Allen, Georgios Anagnostou, Konstantin Androsov, Tagir Aushev, Michele Bianco, Xin Chen, Yixing Chen, Tian Cheng, Davide Cieri, Giuseppe Codispoti, Pratyush Das, Abhisek Datta, Milos Dordevic, Dipanwita Dutta, Matthias Finger, Francesco Fiori, Daniel Gonzalez, Ruchi Gupta, Seungkyu Ha, Csaba Hajdu, Peter Hansen, Ali Harb, Miao Hu, Alexis Kalogeropoulos, Viktor Khristenko, Ji Hyun Kim, Donghyun Kim, Sanjeev Kumar, Ajay Kumar, Vineet Kumar, Ekaterina Kuznetsova, Jing Li, Ho Ling Li, Wei Li, Lei Li, Zhen Liu, Hao Liu, Werner Lustermann, Bibhuprasad Mahakud, Maren Tabea Meinhard, Amr Mohamed, Thomas Muller, Ioannis Papadopoulos, Vladimir Petrov, Quentin Python, Andrea Rizzi, Paolo Ronchese, Sourav Sen, Varun Sharma, Ashish Sharma, Lesya Shchutska, Wei Shi, Kun Shi, Muhammad Shoaib, Jan Steggemann, Marco Trovato, Andromachi Tsirou, David Vannerom, Joao Varela, Zheng Wang, Siyuan Wang, Yi Wang, Qian Wang, Hui Wang, Xiao Wang, Jian Wang, Mingkui Wang, Muhammad Waqas, Matthias Weber, Matthias Wolf, Fan Xia, Meng Xiao, Yong Yang

A search for new light bosons decaying into muon pairs is presented using a data sample corresponding to an integrated luminosity of 35.9 fb−1 of proton-proton collisions at a center-of-mass energy s=13TeV , 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 from the predicted background is observed. A model independent limit is set on the product of the production cross section times branching fraction to dimuons squared times acceptance as a function of new light boson mass. This limit varies between 0.15 and 0.39 fb over a range of new light boson masses from 0.25 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 nonnegligible light boson lifetimes. In both cases, there is significant improvement over previously published limits.

2019