arXiv subjects

Prashant Shukla

Publications and source records attributed to Prashant Shukla.

At least 37 records · Page 2Linked to original sources

arXiv2022

Measurement of atmospheric muon angular distribution using a portable setup of liquid scintillator bars

Measurements of cosmogenic particles at various locations and altitudes are becoming increasingly important in view of worldwide interests in rare signals for search of new physics. In this work, we report measurement of muon zenith angle distributions and integrated flux using a portable setup of four one-meter long liquid scintillator bars. Each scintillator bar is read out from both sides via photomultiplier tubes followed by an 8-channel Digitizer. We exploit energy deposition and excellent timing of scintillators to construct two dimensional tracks and hence angles of charged particles. We use liquid scintillators since they have an added advantage of pulse shape discrimination (PSD) which can be used for detecting muon induced particles. The energy deposition, time window of event and PSD cuts are used to reduce the random as well as correlated backgrounds. In addition, we propose three track quality parameters which are applied to obtain a clean muon spectrum. The zenith angle measurement is performed upto $60^\circ$. With our improved analysis, we demonstrate that a setup of 3 bars can also be used for quicker and precise measurements. The vertical muon flux measured is $66.70 \pm 0.36 \pm 1.50$ $/m^2/sr/s$ with $n=2.10 \pm 0.05 \pm 0.25 $ in $\cos^n θ$ at the location of Mumbai, India ($19^{\circ}$N, $72.9^{\circ}$E) at Sea level with a muon momentum above $255$ MeV/$c$. The muon flux has dependence on various factors, the most prominents are latitudes, altitudes and momentum cut of muon so that portable setup like this can be a boon for such measurements at various locations.

physics.ins-det↗

arXiv2021

Bottomonia production in p+p collisions under NRQCD formalism

In this work, we present the calculation of the production cross sections of bottomonia states using Non-Relativistic Quantum Chromodynamics (NRQCD) formalism. The direct production cross-section of a resonance can be factorised in terms of short distance Quantum Chromodynamics (QCD) cross sections and long distance matrix elements (LDMEs) under NRQCD. We use a large set of measured $Υ$(nS) production data at Tevatron and LHC energies in both central and forward rapidity regions to extract the LDMEs with better precision. The feed down contributions from the higher states including the $χ_{b}$(3P) state are taken into account for the LDME extraction. The formalism provides a good description of the bottomonia data in wide transverse momentum range at different collision energies.

hep-ph↗

arXiv2021

Understanding partonic energy loss from measured light charged particles and jets in PbPb collisions at LHC energies

We perform a comprehensive study of partonic energy loss reflected in the nuclear modification factors of charged particles and jets measured in PbPb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 and 5.02 TeV in wide transverse momentum ($p_{\rm T}$) and centrality range. The $p_{\rm T}$ distributions in pp collisions are fitted with a modified power law and the nuclear modification factor in PbPb collisions can be obtained using effective shift ($Δp_{\rm T}$) in the spectrum measured at different centralities. Driven by physics consideration, the functional form of energy loss given by $Δp_{\rm T}$ can be assumed as power law with different power indices in three different $p_{\rm T}$ regions. The power indices and the boundaries of three $p_{\rm T}$ regions are obtained by fitting the measured nuclear modification factor as a function of $p_{\rm T}$ in all collision centralities simultaneously. The energy loss in different collisions centralities are described in terms of fractional power of number of participants. It is demanded that the power law functions in three $p_T$ regions and their derivatives are continuous at the $p_{\rm T}$ boundaries. The $Δp_{\rm T}$ for light charged particles is found to increase linearly with $p_{\rm T}$ in low $p_{\rm T}$ region below $\sim 5-6$ GeV/$c$ and approaches a constant value in high $p_{\rm T}$ region above $\sim 22-29$ GeV/$c$ with an intermediate power law connecting the two regions. The method is also used for jets and it is found that for jets, the $Δp_{\rm T}$ increases approximately linearly even at very high $p_{\rm T}$.

hep-ph↗

arXiv2019

Suppression of quarkonia in PbPb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV

We study different processes responsible for the modification of quarkonia yields in the medium produced in PbPb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV. The quarkonia and heavy flavour cross sections are estimated using the measurements in pp collisions at LHC energies and shadowing corrections are obtained using the EPS09 parametrizations. A kinetic model is used which incorporates quarkonia suppression inside the Quark Gluon Plasma (QGP), suppression due to hadronic comovers, and regeneration from recombination of heavy quark pairs. The quarkonia dissociation cross section due to gluon collisions, including both color-electric dipole and color-magnetic dipole transitions, has been employed. The regeneration rate is obtained using the principle of detailed balance. The effect of these processes on the nuclear modification factors for both $\Jpsi$ and $Υ$ in different ranges of transverse momentum $\pT$ and rapidity has been studied for PbPb collisions at $\sNN =$ 5.02 TeV. The calculations are compared with the available results from LHC experiments. Both the suppression and regeneration due to a QGP are effective in the low and intermediate $\pT$ range. The large observed suppression of $\Jpsi$ at $\pT~>$ 10 GeV/$c$ is larger than the suppression expected due to gluon dissociation.

hep-ph↗

arXiv2018

Energy and angular distributions of atmospheric muons at the Earth

A fair knowledge of the atmospheric muon distributions at Earth is a prerequisite for the simulations of cosmic ray setups and rare event search detectors. A modified power law is proposed for atmospheric muon energy distribution which gives a good description of the cosmic muon data in low as well as high energy regime. Using this distribution, analytical forms for zenith angle ($θ$) distribution are obtained. Assuming a flat Earth, it leads to the $\cos^{n-1}θ$ form where it is shown that the parameter $n$ is nothing but the power of the energy distribution. Exact analytical function is obtained for inclined trajectory of muon. A new closed form for zenith angle distribution is obtained without assuming a flat Earth and which gives an improved description of the data at all angles even above $70^o$. These distributions are tested with the available atmospheric muon data of energy and angular distributions. The parameters of these distributions can be used to characterize the cosmic muon data as a function of energy, angle and altitude.

hep-ph↗

arXiv2018

Charged current deep inelastic scattering of muon neutrinos off ^{56}Fe

In this paper, we study charged current deep inelastic scattering of muon neutrinos off ^{56}Fe nuclei using Hirai, Kumano and Saito model. The LHA Parton Distribution Functions (PDFs) - CT10 are used to describe the partonic content of hadrons. Modification of PDFs inside the nuclei is done using EPPS16 parameterization at next-to-leading order. Target mass correction has also been incorporated in the calculations. We calculate the structure functions (F_{2}(x,Q^{2}) and xF_{3}(x,Q^{2})), the ratios (R_{2}(x,Q^{2}) = \frac{F^{^{56}Fe}_{2}}{F^{Nucleon}_{2}} and R_{3}(x,Q^{2}) = \frac{F^{^{56}Fe}_{3}}{F^{Nucleon}_{3}}) and the differential cross sections of muon neutrino deep inelastic scattering off a nucleon and ^{56}Fe nuclei. We compare the obtained results with measured experimental data. The present theoretical approach gives a good description of data.

hep-ph↗

arXiv2018

Charged current quasi elastic scattering of muon anti-neutrino off ^{12}C

In this work, we study charged current quasi elastic scattering of muon anti-neutrino off nucleon and nucleus using a formalism based on Llewellyn Smith (LS) model. Parameterizations by Galster et al. are used for electric and magnetic Sach's form factors of nucleons. We use Fermi gas model along with Pauli suppression condition to take into account the nuclear effects in anti-neutrino - nucleus QES. We calculate muon anti-neutrino-p and muon anti-neutrino-^{12}C charged current quasi elastic scattering differential and total cross sections for different values of axial mass M_{A} and compare the results with data from GGM, SKAT, BNL, NOMAD, MINERvA and MiniBooNE experiments. The present theoretical approach gives an excellent description of differential cross section data. The calculations with axial mass M_{A} = 0.979 and 1.05 GeV are compatible with data from most of the experiments.

hep-ph↗

arXiv2018

Charged and Neutral Current Pion Production in Neutrino-Nucleus Scattering

In this article, we present the charged and neutral current coherent pion production in the neutrino-nucleus interaction in the resonance region using the formalism based on the partially conserved axial current (PCAC) theorem which relates the neutrino-nucleus cross section to the pion-nucleus elastic cross section. The pion nucleus elastic cross section is calculated using the Glauber model approach. We calculate the integrated cross sections for neutrino-carbon, neutrino-iron and neutrino-oxygen scattering. The results of integrated cross-section calculations are compared with the measured data

hep-ph↗

arXiv2018

Freeze-out of Strange Hadron in pp, pPb and PbPb Collisions at LHC Energies

In this article, we will present a systematic analysis of transverse momentum spectra of the strange hadron in different multiplicity events produced in pp collision at $\sqrt{s}$ = 7 TeV, pPb collision at $\sqrt{s_{NN}}$ = 5.02 TeV and PbPb collision at $\sqrt{s_{NN}}$ = 2.76 TeV. The differential freeze out scenario of strange hadron $K^{0}_{s}$ assumed while analyzing the data using a Tsallis distribution which is modified to include transverse flow. The $p_{T}$ distributions of strange hadron in different systems are characterized in terms of the parameters namely, Tsallis temperature ($T$), power ($n$) and average transverse flow velocity ($β$).

hep-ph↗

arXiv2018

Transverse momentum spectra of hadrons in high energy pp and heavy ion collisions

We present a study of transverse momentum ($p_{T}$) spectra of unidentified charged particles in pp collisions at RHIC and LHC energies from $\sqrt{s}$ = 62.4 GeV to 13 TeV using Tsallis/Hagedorn function. The power law of Tsallis/Hagedorn form gives excellent description of the hadron spectra in $p_{T}$ range from 0.2 to 300 GeV/$c$. The power index $n$ of the $p_T$ distributions is found to follow a function of the type $a+b/\sqrt {s}$ with asymptotic value $a = 5.72$. The parameter $T$ governing the soft bulk contribution to the spectra remains almost same over wide range of collision energies. We also provide a Tsallis/Hagedorn fit to the $p_{T}$ spectra of hadrons in pPb and different centralities of PbPb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV. The data/fit shows deviations from the Tsallis distribution which become more pronounced as the system size increases. We suggest simple modifications in the Tsallis/Hagedorn power law function and show that the above deviations can be attributed to the transverse flow in low $p_T$ region and to the in-medium energy loss in high $p_T$ region.

hep-ph↗

arXiv2017

Effect of the chromo-electromagnetic field fluctuations on heavy quark propagation at the LHC energies

We consider the effect of the chromo-electromagnetic field fluctuations in addition to the collisional as well as the radiative energy loss suffered by heavy quarks while propagating through the hot and densed deconfined medium of quarks and gluons created in relativistic heavy ion collisions. The chromo-electromagnetic field fluctuations play an important role as it leads to an energy gain of heavy quarks of all momentum, significantly effective at the lower momentum region. With this, we have computed, for the first time, the nuclear modification factor (R_{AA}) of heavy mesons, viz., D-mesons and B-mesons and compared with the those experimental measurements in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV and \sqrt{s_{NN}} = 5.02 TeV by the CMS and ALICE experiments at the LHC. Our results are found to be in very good agreement with those available data measured by CMS and ALICE experiments.

hep-ph↗

arXiv2017

Charged current quasi elastic scattering of muon neutrino with nuclei

We present a study on the charge current quasi elastic scattering of $ν_μ$ from nucleon and nuclei which gives a charged muon in the final state. To describe nuclei, the Fermi Gas model has been used with proposed Pauli suppression factor. The diffuseness parameter of the Fermi distribution has been obtained using experimental data. We also investigate different parametrizations for electric and magnetic Sach's form factors of nucleons. Calculations have been made for CCQES total and differential cross sections for the cases of $ν_μ-N$, $ν_μ-^{12}C$ and $ν_μ-^{56}Fe$ scatterings and are compared with the data for different values of the axial mass. The present model gives excellent description of measured differential cross section for all the systems.

hep-ph↗

arXiv2017

Charmonia production in p+p collisions under NRQCD formalism

This work presents the differential charmonia production cross sections in high energy p+p collisions calculated using NRQCD formalism. The NRQCD formalism, factorizes the quarkonia production cross sections in terms of short distance QCD cross sections and long distance matrix elements (LDMEs). The short distance cross sections are calculated in terms of perturbative QCD and LDMEs are obtained by fitting the experimental data. Measured transverse momentum distributions of $χ_{\rm c}$, $ψ$(2S) and J/$ψ$ in p +{$\bar {\rm p}$} collisions at $\sqrt{s}=$ 1.8, 1.96 TeV and in p+p collisions at $\sqrt{s}=$ 7, 8 and 13 TeV are used to constrain LDMEs. The feed-down contribution to each state from the higher states are taken into account. The formalism provides a very good description of the data in a wide energy range. The values of LDMEs are used to predict the charmonia cross sections in p+p collisions at 13 and 5 TeV in kinematic bins relevant for the LHC detectors.

hep-ph↗

arXiv2017

Strange hadron production in pp, pPb and PbPb collisions at LHC energies

We present a systematic analysis of transverse momentum $(p_{T})$ spectra of the strange hadrons in different multiplicity events produced in pp collision at $\sqrt{s}$ = 7 TeV, pPb collision at $\sqrt{s_{NN}}$ = 5.02 TeV and PbPb collision at $\sqrt{s_{NN}}$ = 2.76 TeV. Both the single and differential freeze out scenarios of strange hadrons $K^0_s$, $Λ$ and $Ξ^-$ are considered while fitting using a Tsallis distribution which is modified to include transverse flow. The $p_{T}$ distributions of these hadrons in different systems are characterized in terms of the parameters namely, Tsallis temperature $(T)$, power $(n)$ and average transverse flow velocity $(β)$. It is found that for all the systems, transverse flow increases as we move from lower to higher multiplicity events. In the case of the differential freeze-out scenario, the degree of thermalization remains similar for events of different multiplicity classes in all the three systems. The Tsallis temperature increases with the mass of the hadrons and also increases with the event multiplicity in pp and pPb system but shows little variation with the multiplicity in PbPb system. In the case of the single freeze-out scenario, the difference between small systems (pp, pPb) and PbPb system becomes more evident. The high multiplicity PbPb events show higher degree of thermalization as compared to the events of pp and pPb systems. The trend of variation of the temperature in PbPb system with event multiplicity is opposite to what is found in the pp and pPb systems.

nucl-th↗

arXiv2017

The Glauber model and heavy ion reaction and elastic scattering cross sections

We revisit the Glauber model to study the heavy ion reaction cross sections and elastic scattering angular distributions at low and intermediate energies. The Glauber model takes nucleon-nucleon cross sections and nuclear densities as inputs and has no free parameter and thus can predict the cross sections for unknown systems. The Glauber model works at low energies down to Coulomb barrier with very simple modifications. We present new parametrization of measured total cross sections as well as ratio of real to imaginary parts of the scattering amplitudes for pp and np collisions as a function of nucleon kinetic energy. The nuclear (charge) densities obtained by electron scattering form factors measured in large momentum transfer range are used in the calculations. The heavy ion reaction cross sections are calculated for light and heavy systems and are compared with available data measured over large energy range. The model gives excellent description of the data. The elastic scattering angular distributions are calculated for various systems at different energies. The model gives good description of the data at small momentum transfer but the calculations deviate from the data at large momentum transfer.

nucl-th↗

arXiv2017

Energy loss of heavy quarks and $B$ and $D$ meson spectra in PbPb collisions at LHC energies

We study the production and evolution of charm and bottom quarks in hot partonic medium produced in heavy ion collisions. The heavy quarks loose energy in the medium which is reflected in the transverse momentum spectra of heavy mesons. The collisional energy loss of heavy quarks has been calculated using QCD calculations. The radiative energy loss is obtained using two models namely reaction operator formalism and generalized dead cone approach. The nuclear modification factors, $R_{AA}$ as a function of transverse momentum by including shadowing and energy loss are calculated for $D^{0}$ and $B^{+}$ mesons in PbPb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV and for $D^{0}$ mesons at $\sqrt{s_{NN}}$ = 2.76 TeV and are compared with the recent measurements. The radiative energy loss from generalized dead cone approach alone is sufficient to produce measured $D^{0}$ meson $R_{AA}$ at both the LHC energies. The radiative energy loss from reaction operator formalism plus collisional energy loss gives good description of $D^{0}$ meson $R_{AA}$. For the case of $B^{+}$ meson, the radiative energy loss from generalized dead cone approach plus collisional energy loss gives good description of the CMS data. The radiative process is dominant for charm quarks while for the bottom, both the radiative process and the elastic collisions are important.

hep-ph↗

arXiv2016

Coherent Pion Production in Neutrino Nucleus Scattering

In this article, we study the coherent pion production in neutrino-nucleus interaction in the resonance region using the formalism based on partially conserved axial current (PCAC) theorem which relates the neutrino-nucleus cross section to the pion-nucleus elastic cross section. The pion nucleus elastic cross section is calculated using the Glauber model in terms of pion-nucleon cross sections obtained by parameterizing the experimental data. We calculate the differential and integrated cross sections for charged current coherent pion production in neutrino carbon scattering. The results of integrated cross section calculations are compared with the measured data. Predictions for the differential and integrated cross sections for coherent pion productions in neutrino iron scattering using above formalism are also made.

hep-ph↗

arXiv2015

Energy loss of $B$ and $D$ mesons in PbPb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV

We present the calculations of collisional and radiative energy loss of $B$ and $D$ mesons in the medium produced in PbPb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. The nuclear modification factor $R_{AA}$ of $B$ and $D$ mesons including shadowing and energy loss are calculated and compared with the measured data. While the $D$ meson $R_{AA}$ can be described in terms of the radiative energy loss alone, both the collisional as well as radiative energy loss are required to explain the $B$ meson measurements.

hep-ph↗