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S. Ghosh

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DOI: 10.1007/jhep12(2021)083
2021
Cited 9 times
Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at $$ \sqrt{s} $$ = 13 TeV
A bstract A search for new top quark interactions is performed within the framework of an effective field theory using the associated production of either one or two top quarks with a Z boson in multilepton final states. The data sample corresponds to an integrated luminosity of 138 fb − 1 of proton-proton collisions at $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 13 TeV collected by the CMS experiment at the LHC. Five dimension-six operators modifying the electroweak interactions of the top quark are considered. Novel machine-learning techniques are used to enhance the sensitivity to effects arising from these operators. Distributions used for the signal extraction are parameterized in terms of Wilson coefficients describing the interaction strengths of the operators. All five Wilson coefficients are simultaneously fit to data and 95% confidence level intervals are computed. All results are consistent with the SM expectations.
DOI: 10.1016/j.nuclphysbps.2015.09.442
2016
Performance of MET reconstruction and pileup mitigation techniques in CMS
The performance of missing transverse momentum reconstruction algorithms is presented using 8 TeV pp collision data collected with the CMS detector, corresponding to an integrated luminosity of $12.2 \pm 0.5$ $\mathrm{fb^{-1}}$. The scale and resolution of missing transverse momentum and the effects of multiple proton-proton interactions (pileup), are measured using events with an identified Z boson or isolated photon. They are in general well described by the simulation. Advanced missing transverse momentum reconstruction algorithms are also developed specifically to mitigate the effects of large numbers of pileup interactions on missing transverse momentum resolution. Using these advanced algorithms, the dependence of the missing transverse momentum resolution on pileup interactions is reduced significantly.
DOI: 10.56726/irjmets42136
2023
Credit Card Fraud Detection Using Machine Learning &amp; Python
In recent years, credit cards have taken on important roles in people's lives.The danger of fraud has increased as a result of the unexpected boom in e-commerce and the widespread usage of credit cards for online purchases.Instead, than carrying around a lot of cash, it is easier to keep credit cards on hand.But that's also dangerous now.A serious problem that is now on the increase dramatically is credit card fraud .Currently, new researchers are having a lot of trouble detecting credit card fraud.We put in place a clever algorithm that can spot any type of fraud in a credit card transaction.By identifying a trend for each consumer in between fraudulent and legal transactions, we were able to solve the issue.The pattern of each customer's transactions is predicted using the isolation forest algorithm and the local outlier factor, and decisions are then made in light of that information.All attributes are tagged similarly to avoid data mismatches.
DOI: 10.3390/universe5010028
2019
Highlights from the Compact Muon Solenoid (CMS) Experiment
The highlights of the recent activities and physics results leading up to the summer of 2018 from the Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider (LHC) are presented here. The CMS experiment has a very wide-ranging physics program, and only a very limited subset of the physics analyses being performed at CMS are discussed here, consisting of several important results from the analysis of proton-proton collision data at center-of-mass energy of 13 TeV. These include important analyses of Higgs boson physics, with the highlight being the first observation of the t t ¯ H production of the Higgs boson, along with analyses pertaining to precision standard model measurements, top quark physics, with the single top production cross-section measurement, and flavor physics, with the important observation of χ b (3P) states. Additionally, important searches for physics beyond the standard model are also presented.
2019
Efficiency of the topological signature in the NEXT-White detector
In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a \TO calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of $71.3 \pm 1.5$ (fit)\% for a background acceptance of $20.3 \pm 0.4$ (fit)\% is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show a slight improvement over those obtained at lower energies.
DOI: 10.1007/978-3-030-53783-8
2020
General Model Independent Searches for Physics Beyond the Standard Model
This book addresses the need for model independent searches for new discoveries in particle physics beyond the standard model with emphasis on the current status of such searches at the LHC and on future experimental improvements involving new tools such as machine learning techniques.
2015
Improving Constraints on Proton Structure using CMS measurements
Production of electroweak bosons, heavy quarks and jets in proton-proton collisions probe different aspects of QCD and are sensitive to the details of proton structure, expressed by parton distribution functions (PDFs). Precise measurements of cross sections of these processes are used by the CMS experiment to demonstrate the impact of the LHC data on the PDFs and their precision. The measurements of muon charge asymmetry in W-boson production at a center-of-mass of 7 and 8 TeV is used to improve the constraints on the valence-quark distributions, while the associated production of W-boson and charm quark provides information on the s-quark distribution in the proton. Production of inclusive jets, as measured by CMS at center-of-mass energy of 7 TeV, provides important constraints on the gluon distribution.
DOI: 10.5167/uzh-140765
2016
Observation of Upsilon(1S) pair production in proton-proton collisions at sqrt(s) = 8 TeV
DOI: 10.22323/1.234.0609
2016
Improving Constraints on Proton Structure using CMS measurements
Production of electroweak bosons, heavy quarks and jets in proton-proton collisions probe different aspects of QCD and are sensitive to the details of proton structure, expressed by parton distribution functions (PDFs). Precise measurements of cross sections of these processes are used by the CMS experiment to demonstrate the impact of the LHC data on the PDFs and their precision. The measurements of muon charge asymmetry in W-boson production at a center-of-mass of 7 and 8 TeV is used to improve the constraints on the valence-quark distributions, while the associated production of W-boson and charm quark provides information on the s-quark distribution in the proton. Production of inclusive jets, as measured by CMS at center-of-mass energy of 7 TeV, provides important constraints on the gluon distribution.
DOI: 10.1016/j.nuclphysbps.2015.09.351
2016
Measurement of the muon charge asymmetry in inclusive pp→W+X production at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>7</mml:mn><mml:mtext> TeV</mml:mtext></mml:math> at CMS and an improved determination of light parton distribution functions
Measurements of the muon charge asymmetry in inclusive $pp \rightarrow WX$ production at $\sqrt{s}=7$ TeV are presented. The data sample corresponds to an integrated luminosity of 4.7 $\mathrm{fb^{-1}}$ recorded with the CMS detector at the LHC. With a sample of more than twenty million $W \rightarrow μν$ events, the statistical precision is greatly improved in comparison to previous measurements. These new results provide additional constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable $x$ from $10^{-3}$ to $10^{-1}$. These measurements are used together with the cross sections for inclusive deep inelastic ep scattering at HERA in a next-to-leading-order QCD analysis.
DOI: 10.48550/arxiv.1512.00632
2015
Improving Constraints on Proton Structure using CMS measurements
Production of electroweak bosons, heavy quarks and jets in proton-proton collisions probe different aspects of QCD and are sensitive to the details of proton structure, expressed by parton distribution functions (PDFs). Precise measurements of cross sections of these processes are used by the CMS experiment to demonstrate the impact of the LHC data on the PDFs and their precision. The measurements of muon charge asymmetry in W-boson production at a center-of-mass of 7 and 8 TeV is used to improve the constraints on the valence-quark distributions, while the associated production of W-boson and charm quark provides information on the s-quark distribution in the proton. Production of inclusive jets, as measured by CMS at center-of-mass energy of 7 TeV, provides important constraints on the gluon distribution.
2017
Latest CMS results on Higgs boson production in association with top quarks ($\mathrm{t\bar{t}H}$)
The searches for Higgs boson production in association with a pair of top quarks at the Compact Muon Solenoid (CMS) experiment using data collected during proton-proton collisions at a center of mass energy of 13 TeV in 2016 are presented. The decay modes of the Higgs boson that are discussed here correspond to the $H \rightarrow ZZ^{*}$, $H \rightarrow WW^{*}$, $H \rightarrow \tau\tau$ and $H \rightarrow \gamma\gamma$ channels.
2017
Latest CMS results on Higgs boson production in association with top quarks
DOI: 10.48550/arxiv.1710.09203
2017
Latest CMS results on Higgs boson production in association with top quarks ($\mathrm{t\bar{t}H}$)
The searches for Higgs boson production in association with a pair of top quarks at the Compact Muon Solenoid (CMS) experiment using data collected during proton-proton collisions at a center of mass energy of 13 TeV in 2016 are presented. The decay modes of the Higgs boson that are discussed here correspond to the $H \rightarrow ZZ^{*}$, $H \rightarrow WW^{*}$, $H \rightarrow \tau\tau$ and $H \rightarrow \gamma\gamma$ channels.
2022
GNN-based end-to-end reconstruction in the CMS Phase 2 High-Granularity Calorimeter
2022
GNN-based end-to-end reconstruction in the CMS Phase 2 High-Granularity Calorimeter
We present the current stage of research progress towards a one-pass, completely Machine Learning (ML) based imaging calorimeter reconstruction. The model used is based on Graph Neural Networks (GNNs) and directly analyzes the hits in each HGCAL endcap. The ML algorithm is trained to predict clusters of hits originating from the same incident particle by labeling the hits with the same cluster index. We impose simple criteria to assess whether the hits associated as a cluster by the prediction are matched to those hits resulting from any particular individual incident particles. The algorithm is studied by simulating two tau leptons in each of the two HGCAL endcaps, where each tau may decay according to its measured standard model branching probabilities. The simulation includes the material interaction of the tau decay products which may create additional particles incident upon the calorimeter. Using this varied multiparticle environment we can investigate the application of this reconstruction technique and begin to characterize energy containment and performance.
DOI: 10.22323/1.314.0286
2018
Latest CMS results on Higgs boson production in association with top quarks $(t\bar tH)$
The searches for Higgs boson production in association with a pair of top quarks at the Compact Muon Solenoid (CMS) experiment using data collected during proton-proton collisions at a center of mass energy of 13 TeV in 2016 are presented. The decay modes of the Higgs boson that are discussed here correspond to the $H \rightarrow ZZ^{*}$, $H \rightarrow WW^{*}$, $H \rightarrow \tau\tau$ and $H \rightarrow \gamma\gamma$ channels.
DOI: 10.1007/978-3-030-53783-8_1
2020
Introduction
Particle physics appears to be entering a new era again. Since the 1960s, it has often been the case that there have been certain compelling theoretical predictions, such as predictions for new fundamental particles, and particle colliders with higher and even higher energies were constructed leading to the discoveries of the predicted particles. This has been the case over the years leading to, most recently, the discovery of the Higgs boson by the ATLAS and CMS experiments at the Large Hadron Collider (LHC). However, we are now at a stage when there is no particular compelling theoretical prediction to go after, with the lack of any major hints of new physics phenomena following the discovery of the Higgs boson.
DOI: 10.22323/1.390.0246
2021
Search for new phenomena in leptonic final states at CMS
Many new physics models, e.g., compositeness, extra dimensions, extended Higgs sectors, supersymmetric theories, and dark sector extensions, are expected to manifest themselves in the final states with leptons.Searches in CMS for new phenomena in the final states that include leptons, focusing on the recent results obtained using the Run-II data set collected at the LHC are described here.