Production of a light top-squark pair in association with a light non-SM Higgs boson within the NMSSM from proton–proton collisions at s = 13 TeV and 33 TeV

2019 ◽  
Vol 34 (22) ◽  
pp. 1950125
Author(s):  
Siba P. Das ◽  
Jorge F. Fraga ◽  
Carlos Avila

We study the production of a light top-squark pair in association with the lightest Higgs boson [Formula: see text], as predicted by the Next-to-Minimal Supersymmetric Standard Model (NMSSM) in proton–proton collisions at center-of-mass energies of 13 TeV and 33 TeV. We scan randomly about 10 million points of the NMSSM parameter space, allowing all possible decays of the lightest top-squark and lightest Higgs boson, with no further assumptions, except for known physical constraints such as perturbative bounds, dark matter relic density consistent with recent Planck experiment measurements, Higgs mass bounds on the next to lightest Higgs boson, [Formula: see text], assuming it is consistent with LHC measurements for the Standard Model Higgs boson, LEP bounds for the chargino mass and [Formula: see text] invisible width, experimental bounds on [Formula: see text] meson rare decays and some LHC experimental bounds on SUSY particle spectra different to the particles involved in our analysis. We find that for low mass top-squark, the dominating decay mode is [Formula: see text] with [Formula: see text]. We use three benchmark points with the highest cross-sections, which naturally fall within the compressed spectra of the top-squark, and make a phenomenological analysis to determine the optimal event selection that maximizes the signal significance over backgrounds. We focus on the leptonic decays of both [Formula: see text]’s and the decay of the lightest Higgs boson into [Formula: see text]-quarks [Formula: see text]. Our results show that the high luminosity LHC will have limitations to observe the studied SUSY scenario and only a proton collider with a collision energy above 33 TeV will be able to observe this signal with more than three standard deviations over background, albeit for stop masses below 300 GeV.

2018 ◽  
Vol 47 ◽  
pp. 1860098
Author(s):  
B. Stugu

Measurements of cross sections and couplings of the Higgs boson using the ATLAS detector at CERN’s LHC are presented. Data from proton proton collisions at [Formula: see text], 8 and 13 TeV are discussed. A range of production and decay couplings can be tested with a precision that depends on the generality of the assumptions made. Data at 7 and 8 TeV are also combined with CMS results to enhance the precision. The results are all consistent with predictions of the Standard Model.


2020 ◽  
Vol 80 (8) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract A data sample of events from proton-proton collisions with at least two jets, and two isolated same-sign or three or more charged leptons, is studied in a search for signatures of new physics phenomena. The data correspond to an integrated luminosity of $$137{\,{\text {fb}}^{-1}} $$137fb-1 at a center-of-mass energy of $$13\,{\text {TeV}} $$13TeV, collected in 2016–2018 by the CMS experiment at the LHC. The search is performed using a total of 168 signal regions defined using several kinematic variables. The properties of the events are found to be consistent with the expectations from standard model processes. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos or squarks for various decay scenarios in the context of supersymmetric models conserving or violating R parity. The observed lower mass limits are as large as $$2.1\,{\text {TeV}} $$2.1TeV for gluinos and $$0.9\,{\text {TeV}} $$0.9TeV for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Measurements of the fiducial inclusive and differential production cross sections of the Higgs boson in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV are performed using events where the Higgs boson decays into a pair of W bosons that subsequently decay into a final state with an electron, a muon, and a pair of neutrinos. The analysis is based on data collected with the CMS detector at the LHC during 2016–2018, corresponding to an integrated luminosity of 137 fb−1. Production cross sections are measured as a function of the transverse momentum of the Higgs boson and the associated jet multiplicity. The Higgs boson signal is extracted and simultaneously unfolded to correct for selection efficiency and resolution effects using maximum-likelihood fits to the observed distributions in data. The integrated fiducial cross section is measured to be 86.5 ± 9.5 fb, consistent with the Standard Model expectation of 82.5 ± 4.2 fb. No significant deviation from the Standard Model expectations is observed in the differential measurements.


2020 ◽  
pp. 2141003
Author(s):  
Joon-Bin Lee ◽  
Jehyun Lee

We present the implementation in the MadAnalysis 5 framework of the CMS-HIG-18-011 search for exotic decays of the Standard Model Higgs boson, in which the Higgs boson is assumed to decay into a pair of light pseudoscalar [Formula: see text], that then further decay into a di-muon and di-[Formula: see text]-jet final state. This analysis considers proton-proton collisions at a center-of-mass energy of 13 TeV and data collected by the CMS experiment in 2016, with an integrated luminosity of 35.9 fb[Formula: see text]. We present a selection of recast predictions, obtained with MadAnalysis 5 and Delphes 3, that include a few differential distributions, yields, and efficiencies. We show that they agree at a level of a few percent with public CMS results.


Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Central exclusive and semiexclusive production of "Equation missing" pairs is measured with the CMS detector in proton-proton collisions at the LHC at center-of-mass energies of 5.02 and 13TeV. The theoretical description of these nonperturbative processes, which have not yet been measured in detail at the LHC, poses a significant challenge to models. The two pions are measured and identified in the CMS silicon tracker based on specific energy loss, whereas the absence of other particles is ensured by calorimeter information. The total and differential cross sections of exclusive and semiexclusive central "Equation missing" production are measured as functions of invariant mass, transverse momentum, and rapidity of the "Equation missing" system in the fiducial region defined as transverse momentum "Equation missing" and pseudorapidity "Equation missing". The production cross sections for the four resonant channels "Image missing" , "Equation missing", "Image missing" , and "Image missing" are extracted using a simple model. These results represent the first measurement of this process at the LHC collision energies of 5.02 and 13TeV.


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
T. Bergauer ◽  
...  

Abstract The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13 TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb−1. The differential production cross sections of the D∗±, D±, and D0$$ \left({\overline{\mathrm{D}}}^0\right) $$ D ¯ 0 mesons are presented in ranges of transverse momentum and pseudorapidity 4 < pT< 100 GeV and |η| < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.


2021 ◽  
Vol 81 (8) ◽  
Author(s):  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
M. Dragicevic ◽  
...  

AbstractA search is presented for a heavy vector resonance decaying into a $${\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}$$ Z boson and the standard model Higgs boson, where the $${\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}$$ Z boson is identified through its leptonic decays to electrons, muons, or neutrinos, and the Higgs boson is identified through its hadronic decays. The search is performed in a Lorentz-boosted regime and is based on data collected from 2016 to 2018 at the CERN LHC, corresponding to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb - 1 . Upper limits are derived on the production of a narrow heavy resonance $${\mathrm{{{\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}}}}_{\mathrm{}}^{\mathrm{\prime }}$$ Z ′ , and a mass below 3.5 and 3.7$$\,\text {Te}\text {V}$$ Te is excluded at 95% confidence level in models where the heavy vector boson couples predominantly to fermions and to bosons, respectively. These are the most stringent limits placed on the Heavy Vector Triplet $${\mathrm{{{\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}}}}_{\mathrm{}}^{\mathrm{\prime }}$$ Z ′ model to date. If the heavy vector boson couples exclusively to standard model bosons, upper limits on the product of the cross section and branching fraction are set between 23 and 0.3$$\,\text {fb}$$ fb for a $${\mathrm{{{\mathrm{Z}}_{\mathrm{}}^{\mathrm{}}}}}_{\mathrm{}}^{\mathrm{\prime }}$$ Z ′ mass between 0.8 and 4.6$$\,\text {Te}\text {V}$$ Te , respectively. This is the first limit set on a heavy vector boson coupling exclusively to standard model bosons in its production and decay.


2019 ◽  
Vol 199 ◽  
pp. 05010
Author(s):  
Anna Cisek ◽  
Wolfgang Schäfer ◽  
Antoni Szczurek

We discuss the semiexclusive production of vector mesons in protonproton collisions with electromagnetic dissociation of one of the protons. Several differential distribution in missing mass (MX), or single-particle variables related exclusively to the produced vector meson are calculated for pp center-of-mass energies 7 and 13 TeV. The cross sections and some differential distributions are compared to their counterparts for purely exclusive reaction $pp \to pV{\rm{ }}p$. For electromagnetic dissociation the important property is that the $p\gamma^{\bigstar} \to Xp$ transitions are given by the electromagnetic structure function of proton. In our calculations we use different parametrizations of the structure function and discuss how it is constrained by the data on virtual photoabsorption on a proton.


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