M. Maity

We describe the design, construction and performance of the upgraded DO muon system for Run II of the Fermilab Tevatron collider. Significant improvements have been made to the major subsystems of the DO muon detector: trigger scintillation counters, tracking detectors, and electronics. The Run II central muon detector has a new scintillation counter system inside the iron toroid and an improved scintillation counter system outside the iron toroid. In the forward region, new scintillation counter and tracking systems have been installed. Extensive shielding has been added in the forward region. A large fraction of the muon system electronics is also new.

We present measurements of the reduction of light output by plastic scintillators irradiated in the CMS detector during the 8 TeV run of the Large Hadron Collider and show that they indicate a strong dose rate effect. The damage for a given dose is larger for lower dose rate exposures. The results agree with previous measurements of dose rate effects, but are stronger due to the very low dose rates probed. We show that the scaling with dose rate is consistent with that expected from diffusion effects.

Purpose The prevalence of dry eye disease (DED) is rising among visual display terminal (VDT) users, a trend that correlates with the growing use of digital devices. The prevalence of VDT-associated DED is reported based on dry eye questionnaires; however, VDT's impact on tear film parameters is less understood.

We consider the prospect of lightest neutralino (${\stackrel{\texttildelow{}}{\ensuremath{\chi}}}_{1}^{0}$) as a dark matter candidate in light of recent interesting observations from the XENON100 and CDMS-II experiments in minimal supergravity framework with large $\mathrm{tan}\ensuremath{\beta}$ and nonvanishing ${A}_{0}$. Within the WMAP satisfied zone, there is a large direct detection reach of lighter ${\stackrel{\texttildelow{}}{\ensuremath{\chi}}}_{1}^{0}$ in the lighter Higgs boson mediated resonance annihilation domain of the above scenario. It is seen that the heavier Higgs boson plays a dominating role in the ${\stackrel{\texttildelow{}}{\ensuremath{\chi}}}_{1}^{0}\ensuremath{-}p$ cross section in the associated zone of parameter space in spite of having a larger mass. Possible LHC signatures are discussed.

The search for the top squark (t˜1) within the kinematic reach of Tevatron Run II is of great contemporary interest. Such a t˜1 can explain the baryon asymmetry of the universe provided 120 GeV⩽mt˜1⩽mt. Moreover if Δm≡mt˜1−mχ˜10 is small, where χ˜10 is the lightest supersymmetric particle (LSP), the dark matter relic density as obtained from the WMAP data may be explained via t˜1-LSP coannihilation. In this scenario the decay t˜1→cχ˜10 is likely to occur with 100% branching ratio but for small Δm the conventional di-jet+E̸T signal becomes unobservable. We propose a new search strategy based on the di-jet+E̸T signature accompanied by an isolated cluster of energy which arises from a decaying heavy particle with characteristic decay length. Our preliminary simulations with Pythia indicate that for 100 GeV⩽mt˜1⩽130 GeV this signal may be observable while somewhat lager mt˜1 may still provide hints of new physics.

We consider a scenario of a minimal supersymmetric standard model with $R$-parity violation, where the lightest supersymmetric particle is the lighter bottom squark $({\stackrel{\texttildelow{}}{b}}_{1})$. We study the production of a bottom squark pair at the LHC and their subsequent decays through the baryon number violating operators leading to a top pair with two light quarks. Looking for both semileptonic and fully hadronic (no leptons) final states, we perform cut-based as well as multivariate analyses (MVA) to estimate the signal significance at the 13 TeV run of the LHC. We find that a cut-based analysis can probe bottom squark mass up to $\ensuremath{\sim}750\text{ }\text{ }\mathrm{GeV}$, which may be extended up to $\ensuremath{\sim}850\text{ }\text{ }\mathrm{GeV}$ using MVA with $300\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ integrated luminosity. The fully hadronic final state, however, is not as promising.

Analyzing the ℓ+n-jets+E̸T (where n⩾2) data from Run-I of the Tevatron using the Bayesian technique, we obtain model independent limits on the product BR(t˜1→be+νeχ˜10)×BR(t˜1*→b¯qq¯′χ˜10) for different values of the lighter top squark (t˜1) mass and the lightest supersymmetric particle (χ˜10) mass. The signal events have been simulated by interfacing the 4-body decay of t˜1 at the parton level with the event generator PYTHIA. These limits have been translated into exclusion plots in the mt˜1–mχ˜10 plane, which also turn out to be fairly model independent for fixed values of the BR of the competing loop decay mode t˜1→cχ˜10. Assuming the loop decay BR to be negligible and using the leading order cross section for t˜1t˜1* pair production, we obtain conservatively mt˜1⩾77.0 (74.5) GeV for mχ˜10=5(15)GeV, while for BR(t˜1→cχ˜10)=20%, the corresponding limits are mt˜1⩾68.0 (65.0) GeV. Using the larger next to leading order cross section stronger limits are obtained. For example, if BR(t˜1→cχ˜10)=20%, mt˜1⩾73.0 (72.7) GeV for mχ˜10=5(15)GeV. Our limits nicely complement the ALEPH bounds which get weaker for low mχ˜10.

The scalar partner of the top quark (the stop) is relatively light in many models of supersymmetry breaking. We study the production of stops at the Large Hadron Collider (LHC) and their subsequent decays through baryon-number violating couplings such that the final state contains no leptons. A detailed analysis performed using detector level observables demonstrate that stop masses up to ∼ 600 GeV may be explored at the LHC (at √s = TeV) depending on the branching ratios for such decays and the integrated luminosity available. Extended to other analogous scenarios, the analysis will, generically, probe even larger masses.

The scalar partner of the top quark is relatively light in many models of supersymmetry breaking. We study the production of top squarks (stops) at the Tevatron collider and their subsequent decay through baryon-number violating couplings such that the final state contains no leptons. Performing a detector-level analysis, we demonstrate that, even in the absence of leptons or missing energy, stop masses up to $210\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ can be accessible at the Tevatron.

The PMTs of the CMS Hadron Forward calorimeter were found to generate a large size signal when their windows were traversed by energetic charged particles. This signal, which is due to Čerenkov light production at the PMT window, could interfere with the calorimeter signal and mislead the measurements. In order to find a viable solution to this problem, the response of four different types of PMTs to muons traversing their windows at different orientations is measured at the H2 beam-line at CERN. Certain kinds of PMTs with thinner windows show significantly lower response to direct muon incidence. For the four anode PMT, a simple and powerful algorithm to identify such events and recover the PMT signal using the signals of the quadrants without window hits is also presented. For the measurement of PMT responses to Čerenkov light, the Hadron Forward calorimeter signal was mimicked by two different setups in electron beams and the PMT performances were compared with each other. Superior performance of particular PMTs was observed.

Recently the CDF Collaboration reported a statistically significant excess in the distribution of the dijet invariant mass between 120--160 GeV in $Wjj$ event sample in $4.3\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data and later confirmed with $7.3\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data, which has generated considerable interest. We offer a possible explanation of this observation in the general framework of minimal supersymmetric standard model with $R$-parity violation through resonance production of ${\stackrel{\texttildelow{}}{\ensuremath{\nu}}}_{\ensuremath{\tau}}$ decaying into the LSP ${\stackrel{\texttildelow{}}{\ensuremath{\tau}}}_{1}$ and $W$ boson. We also give the predictions of this scenario for the LHC operating at 7 TeV center of mass energy.

India-based Neutrino Observatory (INO) [1] has proposed construction of a 50k ton magnetised Iron Calorimeter (ICAL) in an underground laboratory located in South India. Main aims of this, now funded project are to precisely study the atmospheric neutrino oscillation parameters and to determine the ordering of neutrino masses [2]. The detector will deploy about 28,800 glass Resistive Plate Chambers (RPCs) of approximately 2 m × 2 m in area. An ICAL RPC detector with a signal pick-up strip pitch of 30 mm, will have 128 analog signals to be readout and processed - 64 each of positive and negative polarity signals. Thus about 3.6 million detector channels are required to be instrumented. We will present in this paper, design of electronics, trigger and data acquisition systems of this ambitious and indigenous experiment as well as its current status of deployment.

New projective prototypes of a scintillator/lead sandwich type sampling calorimeter Shashlik with a silicon preshower detector have been constructed and tested with an electron beam at CERN-SPS. The energy resolution is measured to be 8.7%E(GeV) in stochastic term, 0.330/E(GeV) in noise term and 0.5% in constant term. The angular resolution is better than 70 mradE(GeV).

Abstract Supplying power at low voltage to the front-end electronics of very fast and highly segmented detectors, typical in the experiments at the Large Hadron Collider, involves several issues, including transient currents and voltages. This study investigates a power chain that involves long cables, DC-DC converters, and input filters. Due to the presence of a common ground close to the input of the DC-DC converter, the power chain can run with a lower value of the input supply. It is seen that the capacitor in the input filter plays a significant role in the process of voltage growth at the input of the DC-DC converter. The effects of the ramp during turning ON and OFF the input supply have been studied thoroughly. It is observed that the voltage/current spikes are reduced due to the application of the ramp. It is also observed that the current/voltage, both at the input and the output of the DC-DC converter, goes through some intermediate oscillations due to the existence of threshold voltage for the converters. The choice of the ramp is critical in reducing spikes and should be incorporated into the power supply.

Urine harbors a plethora of biomolecules that await discovery. This study aimed to develop a suitable protein extraction method using a low volume of urine from non-pregnant and pregnant buffaloes; to test the purified proteins for profiling and mass spectrometry analysis. Urine samples from non-pregnant days 0 (estrus), 8, 10, and 15 of cycle animals (n=6) and pregnancy days 15, 30, and 60 (n=5) were collected. Approximately 15mL urine of each animal was subjected to dialysis, vacuum concentration, size-exclusion chromatography, and acetone precipitation for protein isolation. The recovered protein was quantified and analyzed through gel-electrophoresis. Bands of protein differentially expressed were identified, analyzed through mass spectrometry, and searched against the NCBI database. Identification of lactoferrin (LTF) and SLAMF9 was further confirmed by Western blot analysis. The isolated protein was higher in day-30 pregnant urine as compared to day-10 cycling buffalo urine. The cycling buffalo urine sample exhibited 22 protein bands of which 43.4, 24.6, and 23.7 kDa were unique and 40.7 kDa and 38.2 kDa were up-regulated. In contrast, the pregnant urine samples resulted in 21 protein bands of which 46.4, 27.1, 26.8, and 13.9 kDa proteins were unique 114.8 and 82.2 kDa bands up-regulated. The band 82.2 kDa was LTF, 76.7 kDa MARK1, 66.7 kDa serum albumin; and 38.2 kDa SLAMF9 and MARK1 by mass spectrometry. Western blot analysis revealed the LTF is constitutively present in all urine samples. Protein isolation following this method might improve the future analysis of urinary proteins.

In today’s world, the term "endometriosis" is very common among reproductive-aged women and adolescents. Several women suffer from this disease and experience chronic pain. Infertility is experienced by a large number of women with endometriosis. With the occurrence of endometriosis, women face different risk factors. The relationship between dietary intake and inflammation occurring due to endometriosis is still not evaluated properly. Various ongoing research works are dealing with to see the effect of dietary substances on the pathological and physiological processes of this disease. According to different cohort studies, various foods such as high calcium, vitamin D, A, C, omega-3, and fish oil-containing foods are proven to reduce the risk of endometriosis. Green vegetables were not found to be associated with the formation of chronic inflammation due to endometriosis. Present review work is undertaken to demonstrate a connection between the occurrence and severity of endometriosis and dietary intake.

This is a summary of the projects undertaken by the working group I on high energy and collider physics.

Production of quarks and gluons in hadron collisions tests Quantum Chromodynamics (QCD) over a wide range of energy. Models of QCD are implemented in event generators to simulate hadron collisions and evolution of quarks and gluons into jets of hadrons. PYTHIA8 uses the parton shower model for simulating particle collisions and is optimized using experimental observations. Recent measurements of event shape variables and jet cross-sections in pp collisions at $\sqrt{s}$ = 13 TeV at the Large Hadron Collider have been used to optimize the parton shower model as used in PYTHIA8.

In some extensions of the standard model with extended Higgs sectors, events from new particle production may pass the selection criteria for Higgs search in different channels at the LHC---14 TeV and mimic Higgs signals. This intriguing possibility is illustrated by PYTHIA based simulations using several representative points in the parameter space of the minimal supersymmetric standard model (MSSM) including a point in the minimal supergravity model consistent with the dark matter (DM) relic density data. Our simulations explore the interplay between the charged Higgs signal and typical squark-gluino events. We argue that the standard selections like the one based on the polarization properties of the $\ensuremath{\tau}$'s from charged Higgs decay, though adequate for handling the SM backgrounds, may not be very efficient in the presence of SUSY backgrounds. We then propose an alternative search strategy based on pure kinematics which sufficiently controls both the SM and the MSSM backgrounds. For charged Higgs masses (${H}^{\ifmmode\pm\else\textpm\fi{}}$) in the deep decoupling regime ($600\text{ }\text{ }\mathrm{GeV}\ensuremath{\lesssim}{m}_{{H}^{\ifmmode\pm\else\textpm\fi{}}}\ensuremath{\lesssim}800\text{ }\text{ }\mathrm{GeV}$) this method works well and extends the LHC reach close to 800 GeV for an integrated luminosity of $30\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ with or without the SUSY background. For a lighter charged Higgs a judicious combination of the old selections and some of the cuts proposed by us may disentangle the Higgs signal from the squark-gluino backgrounds quite effectively.

We study the light output, light collection efficiency and signal timing of a variety of organic scintillators that are being considered for the upgrade of the hadronic calorimeter of the CMS detector. The experimental data are collected at the H2 test-beam area at CERN, using a 150 GeV muon beam. In particular, we investigate the usage of over-doped and green-emitting plastic scintillators, two solutions that have not been extensively considered. We present a study of the energy distribution in plastic-scintillator tiles, the hit efficiency as a function of the hit position, and a study of the signal timing for blue and green scintillators.

All LHC experiments will be upgraded during the next LHC long shutdowns (LS2 and LS3).The increase in resolution and luminosity and the use of more advanced CMOS technology nodes typically implies higher current consumption of the on-detector electronics.In this context, and in view of limiting the cable voltage drop, point-of-load DC-DC converters will be used on detector.This will have a direct impact on the existing powering scheme, implying new AC-DC and/or DC-DC stages as well as changes in the power cabling infrastructure.This paper presents the first results obtained while evaluating different LV powering schemes and distribution layouts for HL-LHC trackers.The precise low voltage power source requirements are being assessed and understood using the CMS tracker upgrade as a use-case.

The production of light H± has been studied in top decays by identifying τ-jets from the decays of H±. A significant excess of t events with τ-jets is seen in most of the (tan β, MH+) parameter space explored. Confirmation of the signal comes from a large deficit of dilepton events in the t sample. According to this study, H± with a mass of up to 160 GeV may be observed and 170 GeV may be excluded from a data sample corresponding to an integrated luminosity of 30 fb−1 at the LHC.

The experiments at the Large Hadron Collider are upgrading their detectors for the coming High Luminosity run. Powering the on board electronics of the highly segmented tracking detectors is a challenge because of the stringent requirements on location, space constraint, fine segmentation, radiation and magnetic field tolerance, thermal loss, etc. Similar issues will be relevant for the future colliding beam experiments, also. This paper reports early studies of the Low Voltage Power Supply for the upgrade of the Outer Tracker detector of the Compact Muon Solenoid experiment. The proposed power chain uses point of load DC-DC converters. The studies, with simulations and experimental measurements, have identified a number of critical issues related to the voltages and currents of the DC-DC converters under different operating conditions. A few constraints on the design of such a system have been identified and in some cases remedial measures to circumvent such constraints have been suggested.

The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with a outer calorimeter to ensure high energy shower containment in CMS and thus working as a tail catcher. Fabrication, testing and calibrations of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing measurements at LHC energies. The outer hadron calorimeter has a very good signal to background ratio even for a minimum ionising particle and can hence be used in coincidence with the Resistive Plate Chambers of the CMS detector for the muon trigger.

We consider a scenario of Minimal Supersymmetric Standard Model (MSSM) with $R$-parity violation, where the lightest supersymmetric particle (LSP) is the lighter sbottom $(\tilde b_1)$. We study the production of sbottom pair at the LHC and their subsequent decays through the Baryon number violating $(U D D)$ operators of the $R$-parity violating MSSM. We choose the type of Baryon number violating operator such that the final state contains top pair with two light quarks. We then look for both semi-leptonic and fully hadronic (no leptons) final states. We perform both cut-based and multivariate analysis (MVA) to estimate the signal significance at the 13 TeV run of the LHC. We show that the sbottom mass $\sim 650 $ GeV (using cut-based analysis) and $\sim 750 $ GeV (using MVA) may be explored in the semi-leptonic channel assuming $300~{\rm fb}^{-1}$ luminosity. Through our MVA analysis we show that the fully hadronic final state is not very promising to explore the LSP sbottom scenario due to large irreducible QCD background.

Recently CDF has reported a 4.1 sigma excess in the distribution of the dijet invariant mass between 120-160 GeV in Wjj event sample in 7.3 fb^{-1} of data, which has generated considerable interest. We offer a possible explanation of this observation in the general framework of MSSM with R-parity violation through resonance production of tau sneutrino decaying into the LSP stau_1 and W boson. We also give the predictions of this scenario for the LHC operating at 7 TeV center of mass energy.

The Phase I upgrade of the CMS Hadron Endcap Calorimeters consists of new photodetectors (Silicon Photomultipliers in place of Hybrid Photo-Diodes) and front-end electronics. The upgrade will eliminate the noise and the calibration drift of the Hybrid Photo-Diodes and enable the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade also includes increased longitudinal segmentation of the calorimeter readout, which allows pile-up mitigation and recalibration due to depth-dependent radiation damage. As a realistic operational test, the responses of the Hadron Endcap Calorimeter wedges were calibrated with a 60Co radioactive source with upgrade electronics. The test successfully established the procedure for future source calibrations of the Hadron Endcap Calorimeters. Here we describe the instrumentation details and the operational experiences related to the sourcing test.

Understanding the production of quarks and gluons in high-energy collisions and their evolution is a very active area of investigation. Monte Carlo event generator pythia8 uses the parton shower model to simulate such collisions and is optimized using experimental observations. Recent measurements of event-shape variables and differential jet cross sections in pp collisions at $$\mathrm {\sqrt{s} = 13\, \text {TeV}}$$ at the Large Hadron Collider have been used to investigate further the parton shower model as used in pythia8.

Production of quarks and gluons in hadron collisions tests Quantum Chromodynamics (QCD) over a wide range of energy. Models of QCD are implemented in event generators to simulate hadron collisions and evolution of quarks and gluons into jets of hadrons. PYTHIA8 uses the parton shower model for simulating particle collisions and is optimized using experimental observations. Recent measurements of event shape variables and jet cross-sections in pp collisions at $\sqrt{s}$ = 13 TeV at the Large Hadron Collider have been used to optimize the parton shower model as used in PYTHIA8.

Shashlik calorimeter prototypes equipped with preshower detector have been tested in 3 T magnetic field with electron beam at CERN-SPS. The signal from electrons increases as much as 11% at 3 T magnetic field. No significant deterioration on the energy resolution as well as the preshower detector performance have been observed.

Understanding the production of quarks and gluons in high energy collisions and their evolution is a very active area of investigation. Monte carlo event generator PYTHIA8 uses the parton shower model to simulate such collisions and is optimized using experimental observations. Recent measurements of event shape variables and differential jet cross-sections in pp collisions at $\surd{s} = 13\, TeV$ at the Large Hadron Collider have been used to investigate further the parton shower model as used in PYTHIA8.

Understanding the production of quarks and gluons in high energy collisions and their evolution is a very active area of investigation. Monte carlo event generator PYTHIA8 uses the parton shower model to simulate such collisions and is optimized using experimental observations. Recent measurements of event shape variables and differential jet cross-sections in pp collisions at $\surd{s} = 13\, TeV$ at the Large Hadron Collider have been used to investigate further the parton shower model as used in PYTHIA8.