A. Nayak

Abstract Many analyses are performed by the LHC experiments to search for heavy gauge bosons, which appear in several new physics models. The invariant mass reconstruction of heavy gauge bosons is difficult when they decay to $$\tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>τ</mml:mi> </mml:math> leptons due to missing neutrinos in the final state. Machine learning techniques are widely utilized in experimental high-energy physics, in particular in analyzing the large amount of data produced at the LHC. In this paper, we study various machine learning techniques to reconstruct the invariant mass of $$Z^{\prime }~\rightarrow ~\tau \tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>Z</mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mspace /> <mml:mo>→</mml:mo> <mml:mspace /> <mml:mi>τ</mml:mi> <mml:mi>τ</mml:mi> </mml:mrow> </mml:math> and $$W^{\prime }~\rightarrow ~\tau \nu $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>W</mml:mi> <mml:mo>′</mml:mo> </mml:msup> <mml:mspace /> <mml:mo>→</mml:mo> <mml:mspace /> <mml:mi>τ</mml:mi> <mml:mi>ν</mml:mi> </mml:mrow> </mml:math> decays, which can improve the sensitivity of these searches.

We analyse the signal sensitivity of multi-lepton final states at collider that can arise from doubly and singly charged Higgs decay in a type-II seesaw framework. We assume triplet vev to be very small and degenerate masses for both the charged Higgs states. The leptonic branching ratio of doubly and singly charged Higgs states have a large dependency on the neutrino oscillation parameters, lightest neutrino mass scale, as well as neutrino mass hierarchy. We explore this as well as the relation between the leptonic branching ratios of the singly and doubly charged Higgs states in detail. We evaluate the effect of these uncertainties on the production cross-section. Finally, we present a detailed analysis of multi-lepton final states for a future hadron collider HE-LHC, that can operate with center of mass energy $\sqrt{s}=27$ TeV.

Predictive-coding has justifiably become a highly influential theory in Neuroscience. However, the possibility of its unfalsifiability has been raised. We argue that if predictive-coding were unfalsifiable, it would be a problem, but there are patterns of behavioural and neuroimaging data that would stand against predictive-coding. Contra (vanilla) predictive patterns are those in which the more expected stimulus generates the largest evoked-response. However, basic formulations of predictive-coding mandate that an expected stimulus should generate little, if any, prediction error and thus little, if any, evoked-response. It has, though, been argued that contra (vanilla) predictive patterns can be obtained if precision is higher for expected stimuli. Certainly, using precision, one can increase the amplitude of an evoked-response, turning a predictive into a contra (vanilla) predictive pattern. We demonstrate that, while this is true, it does not present an absolute barrier to falsification. This is because increasing precision also reduces latency and increases the frequency of the response. These properties can be used to determine whether precision-weighting in predictive-coding justifiably explains a contra (vanilla) predictive pattern, ensuring that predictive-coding is falsifiable.

The Cherenkov Telescope Array will be the next generation ground-based gamma ray observatory in the energy range from a few tens of GeV to hundreds of TeV.It will be built on two sites, one for each hemisphere, to cover the entire sky.The observatory will consist of telescopes of three different sizes: large, medium and small, with primary reflectors of 23, 11.5 and 4.3 m in diameter, respectively.The Small-Sized Telescopes (SSTs) will focus on the highest energies; at least 37 (and up to 70) will be deployed at the southern site in Paranal, Chile, covering several square kilometers.They will have a Schwarzschild-Couder dual-mirror design, with a primary reflector of about 4 meters in diameter.This configuration leads to a compact camera, with a diameter of about 50 cm and a weight of less than 100 kg.Its focal plane consists of 2048 Silicon Photomultiplier pixels, each one read independently by a state-of-the-art full waveform readout.The camera design is now in the final stage and the first components are being tested.In this contribution we discuss the design choices, and present test results from latest developments.

The ATLAS and CMS experiments have performed measurements of the structure of the interaction between the Higgs boson and leptons using proton-proton collisions at √ = 13 TeV, delivered by LHC during 2016-2018.The measurements are based on the angular correlation between the decay planes of leptons produced in Higgs boson decays.The value of the effective mixing angle measured by ATLAS and CMS experiments are found to be 9 ± 16 • and -1 ± 19 • at the 68% CL, respectively.The data from ATLAS and CMS experiments disfavour the pure -odd hypothesis at 3.4 and 3.0 standard deviations, respectively.The results are compatible with expectations for the standard model Higgs boson.

Abstract Vector boson fusion proposed initially as an alternative channel for finding heavy Higgs has now established itself as a crucial search scheme to probe different properties of the Higgs boson or for new physics. We explore the merit of deep-learning entirely from the low-level calorimeter data in the search for invisibly decaying Higgs. Such an effort supersedes decades-old faith in the remarkable event kinematics and radiation pattern as a signature to the absence of any color exchange between incoming partons in the vector boson fusion mechanism. We investigate among different neural network architectures, considering both low-level and high-level input variables as a detailed comparative analysis. To have a consistent comparison with existing techniques, we closely follow a recent experimental study of CMS search on invisible Higgs with 36 fb $$^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow /> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> data. We find that sophisticated deep-learning techniques have the impressive capability to improve the bound on invisible branching ratio by a factor of three, utilizing the same amount of data. Without relying on any exclusive event reconstruction, this novel technique can provide the most stringent bounds on the invisible branching ratio of the SM-like Higgs boson. Such an outcome has the ability to constraint many different BSM models severely.

At the LHC, the gluon-initiated processes are considered to be the primary source of di-Higgs production. However, in the presence of a new resonance, the light-quark initiated processes can also contribute significantly. In this letter, we look at the di-Higgs production mediated by a new singlet scalar. The singlet is produced in both quark-antiquark and gluon fusion processes through loops involving a scalar leptoquark and right-handed neutrinos. With benchmark parameters inspired from the recent resonant di-Higgs searches by the ATLAS collaboration, we examine the prospects of such a resonance in the TeV-range at the High-Luminosity LHC (HL-LHC) in the bb¯τ+τ− mode with a multivariate analysis. We obtain the 5σ and 2σ contours and find that a significant part of the parameter space is within the reach of the HL-LHC.

Abstract A lot of advancement in the field of semiconductors has made it possible to design a solid state neutron detector. They are small in size and compact, have economical bulk fabrications, require low power for their operation. Hence it can act as a plausible alternative to traditional neutron detector such as gas filled and scintillation detectors. It has been observed that many factors like the choice of converter material, LLD settings and geometrical configurations have an impact on the thermal neutron detection efficiency of solid state neutron detector design. Therefore in the present research work, a systematic GEANT4 simulation have been performed on estimating the simulated thermal neutron detection efficiency (η) for five different solid state detector geometrical configurations design with Boron Carbide ( 10 B 4 C) as a converter material. These detectors geometry configurations designs are planar, rectangular parallel trenches, cylindrical perforation, stack and spherical (single and multi-layer). The objective of the simulations was to obtain critical geometrical features for which the efficiency reaches the maximum value, of the given detector configurations. The influence of the different enrichment levels of 10 B (20% to 80%) in Boron Carbide and different Low-Level Discriminator (LLD) value setting (from 100 keV to 700 keV) on the simulated thermal neutron detection efficiency was also investigated. Finally, the simulated multi channel analyzer spectra or in other words histoplots were obtained for all the detector configurations.

Report of the Higgs working group for the Workshop "Physics at TeV Colliders", Les Houches, France 8-18 June 1999. It contains 6 separate sections: 1. Measuring Higgs boson couplings at the LHC. 2. Higgs boson production at hadron colliders at NLO. 3. Signatures of Heavy Charged Higgs Bosons at the LHC. 4. Light stop effects and Higgs boson searches at the LHC. 5. Double Higgs production at TeV Colliders in the MSSM. 6. Programs and Tools for Higgs Bosons.

Many analyses are performed by the LHC experiments to search for heavy gauge bosons, which appear in several new physics models. The invariant mass reconstruction of heavy gauge bosons is difficult when they decay to $τ$ leptons due to missing neutrinos in the final state. Machine learning techniques are widely utilized in experimental high-energy physics, in particular in analyzing the large amount of data produced at the LHC. In this paper, we study machine learning techniques such as supervised and unsupervised neural network algorithms to reconstruct the invariant mass of $Z^{\prime}~\rightarrow~ττ$ and $W^{\prime}~\rightarrow~τν$ decays, which can improve the sensitivity of these searches.

The cross section for production of Z bosons with two associated b-jets, and Z decaying to leptons, can be measured at the LHC with about 100 pb-1 of data. We use simulated data to study possible strategies for an early measurement of this process with the CMS detector. The rate and kinematic properties of this final state needs to be well understood because it constitutes a large fraction of the total backgrounds to several of the Higgs discovery channels at the LHC.

The Froissart bound on the total cross section, ${\ensuremath{\sigma}}_{t}$, is subjected to test against very high energy data. We have found no clear evidence for its violation. The scaling property of the differential cross section in the diffraction region is investigated. It exhibits scaling in the ISR, SPS, Tevatron, and LHC energy domain which had hitherto remained unexplored. The slope of the diffraction peak is fitted and the data are tested against the rigorous bounds.

Abstract The search for new physics at high energy accelerators has been at the crossroads with very little hint of signals suggesting otherwise. The challenges at a hadronic machine such as the LHC is compounded by the fact that final states are swamped with jets which one needs to understand and unravel. A positive step in this direction would be to separate the jets in terms of their gluonic and quark identities, much in a similar spirit of distinguishing heavy quark jets from light quark jets that has helped in improving searches for both neutral and charged Higgs bosons at the LHC. In this work, we utilise this information using the jet substructure techniques to comment on possible improvements in sensitivity as well as discrimination of new resonances in the all hadronic mode that would be crucial in pinning down new physics signals at HL-LHC, HE-LHC and any future 100 TeV hadron collider.

The results of the searches for a Higgs boson decaying to down-type fermions are presented using the proton-proton collision data collected by the ATLAS and CMS experiments at the LHC, at a centre-of-mass energy of 7 and 8 TeV. The results obtained with the available data provides a strong evidence for a Higgs boson coupling to fermions. Results are also presented for a Higgs boson production in association with a pair of top quarks.

We present results from a search for an exotic Higgs boson in the channel H$^{++}$ $\rightarrow ~\ell^{+}\ell^{+}$ with the CMS detector using data accumulated in the 2010 &amp; 2011 running of the LHC at $\sqrt{s}$ = 7 TeV. We also present results from a search for a charged Higgs boson in $t\bar{t}$ decays in the channel H$^{+}$ $\rightarrow$ $τν$

The reconstruction and identification of physics objects in the CMS detector, in the context of the charged Higgs boson search analysis, are presented. The reconstruction algorithms and their performance in 7 TeV and 8 TeV LHC data are discussed. The identification of tau hadronic decays, the reconstruction of hadronic jets and missing transverse energy and the identification of b jets are described in detail.

A search for neutral Higgs bosons in the minimal supersymmetric extension of the Standard Model (MSSM) decaying to a pair of b quarks or a pair of tau leptons, using events recorded by the CMS experiment at the LHC in 2011 and 2012 at the centre-of-mass energy of 7 TeV and 8 TeV respectively, is presented. The result is also presented for a search for the charged Higgs boson that can be produced in the top quark decay with subsequent decay of H+ in tau and neutrino. Results are also reported from a search for non-standard-model Higgs boson decays to pairs of new light bosons, each of which decays into the di-muon final state.

The cross section for production of Z bosons with two associated b-jets, and Z decaying to leptons, can be measured at the LHC with about 100 pb-1 of data. We use simulated data to study possible strategies for an early measurement of this process with the CMS detector. The rate and kinematic properties of this final state needs to be well understood because it constitutes a large fraction of the total backgrounds to several of the Higgs discovery channels at the LHC.

Results of the recent measurements for the inclusive tt production cross section in the protonproton collisions at LHC are presented.The analyses use proton-proton collision data recorded by the ATLAS and CMS experiments at center-of-mass energies of 7, 8, and 13 TeV.Measurements of the production cross sections of ttbb, ttW, ttZ, and ttg processes are also reported.

The cross section for production of Z bosons with two associated b-jets, and Z decaying to leptons, can be measured at the LHC with about 100 pb-1 of data. We use simulated data to study possible strategies for an early measurement of this process with the CMS detector. The rate and kinematic properties of this final state needs to be well understood because it constitutes a large fraction of the total backgrounds to several of the Higgs discovery channels at the LHC.

We analyze the signal sensitivity of multi-lepton final states at the collider that can arise from doubly and singly charged Higgs decay in a type-II seesaw framework. We assume triplet Vacuum Expectation Value (VEV) to be very small and degenerate masses for both the charged Higgs states. The leptonic branching ratio of doubly and singly charged Higgs states have a large dependency on the neutrino oscillation parameters, lightest neutrino mass scale, as well as on neutrino mass hierarchy. We explore this as well as the relation between the leptonic branching ratios of the singly and doubly charged Higgs states in detail. We evaluate the effect of these uncertainties on the production cross-section of multi-lepton signal. Finally, we present a detailed analysis of multi-lepton final states for a future hadron collider HE-LHC, that can plausibly operate with the center of mass energy $$\sqrt{s}=27$$ TeV.

Results of searches for the Higgs boson production in association with a pair of top quarks using the proton-proton collision data collected by the CMS detector at LHC are presented. First, results of the searches at centre-of-mass energy of 13 TeV are briefly discussed. Then, the combination of results at centre-of-mass energies of 7, 8, and 13 TeV are presented, which provides an observation of the Higgs boson production in association with a pair of top quarks with a significance of 5.2 standard deviations.

Results of searches for the Higgs boson production in association with a pair of top quarks using the proton-proton collision data collected by the CMS detector at LHC are presented.First, results of the searches at centre-of-mass energy of 13 TeV are briefly discussed.Then, the combination of results at centre-of-mass energies of 7, 8, and 13 TeV are presented, which provides an observation of the Higgs boson production in association with a pair of top quarks with a significance of 5.2 standard deviations.

The search for new physics at high energy accelerators has been at the crossroads with very little hint of signals suggesting otherwise. The challenges at a hadronic machine such as the LHC compounds on the fact that final states are swamped with jets which one needs to understand and unravel. A positive step in this direction would be to separate the jets in terms of their gluonic and quark identities, much in similar spirit of distinguishing heavy quark jets from light quark jets that has helped in improving searches for both neutral and charged Higgs bosons at the LHC. In this work, we utilise this information using the jet substructure techniques to comment on possible improvements in sensitivity as well as discrimination of new resonances in the all hadronic mode that would be crucial in pinning down new physics signals at HL-LHC, HE-LHC and any future 100 TeV hadron collider.

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Results of searches for the Higgs boson production in association with a pair of top quarks using the proton-proton collision data collected by the CMS detector at LHC are presented. First, results of the searches at centre-of-mass energy of 13 TeV are briefly discussed. Then, the combination of results at centre-of-mass energies of 7, 8, and 13 TeV are presented, which provides an observation of the Higgs boson production in association with a pair of top quarks with a significance of 5.2 standard deviations.