arXiv subjects

Arvind Kumar

Publications and source records attributed to Arvind Kumar.

At least 127 records · Page 7Linked to original sources

arXiv2019

Regularity of binomial edge ideals of Cohen-Macaulay bipartite graphs

Let $G$ be a finite simple graph on $n$ vertices and $J_G$ denote the corresponding binomial edge ideal in $S = K[x_1, \ldots, x_n, y_1, \ldots, y_n].$ In this article, we prove that if $G$ is a fan graph of a complete graph, then $reg(S/J_G) \leq c(G)$, where $c(G)$ denote the number of maximal cliques in $G$. Further, we show that if $G$ is a $k$-pure fan graph, then $reg(S/J_G) = k+1$. We then compute a precise expression for the regularity of Cohen-Macaulay bipartite graphs.

math.AC↗

arXiv2018

Octet Baryon Masses and Magnetic Moments in Hot and Dense Isospin Asymmetric Nuclear Matter

Medium modification of the magnetic moments of octet baryons in the isospin asymmetric nuclear medium at finite temperature has been calculated using medium modified quark and baryon masses derived in chiral SU(3) quark mean field model. The magnetic moments of baryons are found to vary significantly as a function of density of nuclear medium as well as with the increase in isospin asymmetry of the medium. The rise of temperature is found to decrease the effect of isospin asymmetry on masses and magnetic moments of baryons. The results of present investigation may be helpful to understand the experimentally observed values of octet baryon magnetic moments at different experimental facilities.

nucl-th↗

arXiv2018

In-medium masses and magnetic moments of decuplet baryons

The magnetic moments of baryon decuplet are studied in vacuum as well as in the symmetric nuclear matter at finite temperature using a chiral SU(3) quark mean field model approach. The contributions coming from the valence quarks, quark sea and the orbital angular momentum of the quark sea have been considered to calculate magnetic moment of decuplet baryons. The decuplet baryon masses decrease, whereas, the magnetic moments increase significantly with the rise of baryonic density of the symmetric nuclear medium. This is because of the reason that constituent quark magnetic moment and the quark spin polarizations show considerable variation in the nuclear medium especially in the low temperature and baryonic density regime. The increase is however quantitatively less as compared to the case of octet baryon members.

hep-ph↗

arXiv2018

$J/ψ$ and $η_c$ in asymmetric hot magnetized nuclear matter

We investigate the mass-shift of vector channel $J/ψ$ and pseudoscalar channel $η_c$ in strongly magnetized asymmetric nuclear medium at finite temperature using the conjunction of chiral $SU(3)$ model with the QCD sum rules. The magnetic field dependence of scalar gluon condensate $\left\langle \frac{α_{s}}π G^a_{μν} {G^a}^{μν} \right\rangle$ as well as the twist-2 gluon condensate $\left\langle \frac{α_{s}}π G^a_{μσ} {{G^a}_ν}^σ \right\rangle $ calculated from chiral SU($3$) model, are implemented in QCD sum rules to calculate the magnetic field dependence of $J/ψ$ and $η_c$ meson masses. The effects of constant external magnetic field at finite density and temperature of the medium are found to be appreciable in symmetric and asymmetric nuclear matter. The results of the present investigation may be helpful to understand the experimental observables arising from the Compressed Baryonic Matter (CBM) produced in asymmetric non-central heavy ion collision experiments.

hep-ph↗

arXiv2017

In-medium properties of pseudoscalar $D_s$ and $B_s$ mesons

We calculate the shift in masses and decay constants of $D_s(1968)$ and $B_s(5370)$ mesons in hot and dense asymmetric strange hadronic matter using QCD sum rules and chiral SU(3) model. In-medium strange quark condensates $\left\langle \bar{s}s\right\rangle_{ρ_B}$, and gluon condensates $\left\langle \frac{α_{s}}π {G^a}_{μν} {G^a}^{μν} \right\rangle_{ρ_B}$ to be used in the QCD sum rules for pseudoscalar $D_s$ and $B_s$ mesons are calculated using chiral SU(3) model. As an application of our present work, we calculate the in-medium decay widths of the excited (c$\bar{s}$) states $D_s^*(2715)$ and $D_s^*(2860)$ decaying to ($D_s(1968)$,$η$) mesons. The medium effects in their decay widths are incorporated through the mass modification of the $D_s(1968)$ and $η$ mesons. Results of the present investigation may be helpful to understand the possible outcomes of the future experiments like CBM and PANDA under the FAIR facility.

hep-ph↗

arXiv2017

Masses and decay widths of scalar $D_0$ and $D_{s0}$ mesons in strange hadronic medium

Masses and decay constants of scalar $D_0$ and $D_{s0}$ mesons in isospin asymmetric strange hadronic matter at finite temperature are evaluated using QCD sum rules and chiral SU(3) model. In-medium light quark condensates, $\left\langle \bar{u}u\right\rangle_{ρ_{B}}$ and $\left\langle \bar{d}d\right\rangle_{ρ_{B}}$, the strange quark condensates, $\left\langle \bar{s}s\right\rangle_{ρ_{B}}$, and the gluon condensates, $\left\langle \frac{α_{s}}π {G^a}_{μν} {G^a}^{μν} \right\rangle_{ρ_{B}}$, needed in QCD sum rule calculations are evaluated using chiral SU(3) model. As an application, we calculate the in-medium partial decay width of scalar $D_0$ ($D_{s0}$) meson decaying to $D$ + $π$ ($D_s$+$π$) pseudoscalar mesons using $^3 P_0$ model. The medium effects in their decay widths are assimilated through the modification in the masses of these mesons. These results may be helpful to understand the possible outcomes of the future experiments like CBM and PANDA under the FAIR facility where the study of charmed hadrons is one of major goal.

hep-ph↗

arXiv2017

Magnetic Moments of Octet Baryons in Hot and Dense Nuclear Matter

We have calculated the in-medium magnetic moments of octet baryons in the presence of hot and dense symmetric nuclear matter. Effective magnetic moments of baryons have been derived from medium modified quark masses within chiral SU(3) quark mean field model. Further, for better insight of medium modification of baryonic magnetic moments, we have considered the explicit contributions from the valence quarks, sea quarks as well as sea orbital angular momentum of sea quarks. These effects have been successful in giving the description of baryonic magnetic moments in vacuum. The magnetic moments of baryons are found to vary significantly as a function of density of nuclear medium.

hep-ph↗

arXiv2017

The adjoint map of the Serre derivative and special values of shifted Dirichlet series

We compute the adjoint of the Serre derivative map with respect to the Petersson scalar product by using existing tools of nearly holomorphic modular forms. The Fourier coefficients of a cusp form of integer weight $k$, constructed using this method, involve special values of certain shifted Dirichlet series associated with a given cusp form $f$ of weight $k+2$. As application, we get an asymptotic bound for the special values of these shifted Dirichlet series and also relate these special values with the Fourier coefficients of $f$. We also give a formula for the Ramanujan tau function in terms of the special values of the shifted Dirichlet series associated to the Ramanujan delta function.

math.NT↗

arXiv2016

In-medium pseudoscalar $D/B$ mesons and charmonium decay width

Using QCD sum rules and chiral SU(3) model, we investigate the effect of temperature, density, strangeness fraction and isospin asymmetric parameter on the shift in masses and decay constants of the pseudoscalar $D$ and $B$ meson in hadronic medium, which consist of nucleons and hyperons. The in-medium properties of $D$ and $B$ mesons within QCD sum rule approach depend upon the quark and gluon condensates. In chiral SU(3) model, quark and gluon condensates are introduced through the explicit symmetry breaking term and the trace anomaly property of the QCD, respectively and are written in terms of scalar fields $σ$, $ζ$, $δ$ and $χ$. Hence, through medium modification of $σ$, $ζ$, $δ$ and $χ$ fields, we obtain the medium modified masses and decay constants of $D$ and $B$ mesons. As an application, using $^3 P_0$ model, we calculate the in-medium decay width of the higher charmonium states $ ψ(3686)$, $ψ(3770)$ and $χ(3556)$ to the $D \bar{D}$ pairs, considering the in-medium mass of $D$ mesons. These results may be important to understand the possible outcomes of high energy physics experiments, e.g., CBM and PANDA at GSI, Germany.

hep-ph↗

arXiv2016

Construction of cusp forms using Rankin-Cohen brackets

For a fix modular form g and a non negative ineteger ν, by using Rankin-Cohen bracket we first define a linear map $T_{g,ν}$ on the space of modular forms. We explicitly compute the adjoint of this map and show that the n-th Fourier coefficients of the image of the cusp form f under this map is, upto a constant a special value of Rankin-Selberg convolution of f and g.

math.NT↗

arXiv2015

Heavy Vector and Axial-Vector Mesons in Hot and Dense Asymmetric Strange Hadronic Matter

We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\left( D^{\ast}, D_{s}^{\ast}, B^{\ast}, B_{s}^{\ast}\right)$ and axial-vector $\left( D_{1}, D_{1s}, B_{1}, B_{1s}\right)$ mesons, using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In QCD sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons are written in terms of quark and gluon condensates. These quark and gluon condensates are evaluated in the present work within chiral SU(3) model, through the medium modification of, scalar-isoscalar fields $σ$ and $ζ$, the scalar-isovector field $δ$ and scalar dilaton field $χ$, in the strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail, the masses and decay constants of heavy vector and axial-vector mesons are affected significantly due to isospin asymmetry and strangeness fraction of the medium and these modifications may influence the experimental observables produced in heavy ion collision experiments. The results of present investigations of in-medium properties of vector and axial-vector mesons at finite density and temperature of strange hadronic medium may be helpful for understanding the experimental data from heavy-ion collision experiments in-particular for the Compressed Baryonic Matter (CBM) experiment of FAIR facility at GSI, Germany.

nucl-th↗

arXiv2015

Optimal Release Time Decision from Fuzzy Mathematical Programming Perspective

Demand for high software reliability requires rigorous testing followed by requirement of robust modeling techniques for software quality prediction. On one side, firms have to steadily manage the reliability by testing it vigorously, the optimal release time determination is their biggest concern. In past many models have been developed and much research has been devoted towards assessment of release time of software. However, majority of the work deals in crisp study. This paper addresses the problem of release time prediction using fuzzy Logic. Here we have formulated a Fuzzy release time problem considering the cost of testing under the impact of warranty period. Results show that fuzzy model has good adaptability.

cs.AI↗

arXiv2015

Heavy Vector and Axial-Vector Mesons in Asymmetric Strange Hadronic Matter

We calculate the effects of finite density of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\left( D^{\ast}, D_{s}^{\ast}, B^{\ast}, B_{s}^{\ast}\right)$ and axial-vector $\left( D_{1}, D_{1s}, B_{1}, B_{1s}\right)$ mesons using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift of decay constant of above vector and axial vector mesons. In QCD sum rule approach the properties e.g. masses and decay constants of vector and axial vector mesons are written in terms of quark and gluon condensates. These quarks and gluon condensates are evaluated in the present work using chiral SU(3) model through the medium modification of scalar-isoscalar fields $σ$ and $ζ$, the scalar-isovector field $δ$ and scalar dilaton field $χ$ in strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail the masses and decay constants of heavy vector and axial vector mesons are affected significantly due to isospin asymmetry and strangeness fraction of the medium and these modifications may influence the experimental observables produced in heavy ion collision experiments. The results of present investigations of in-medium properties of vector and axial-vector mesons at finite density of strange hadronic medium may be helpful for understanding the experimental data from heavy-ion collision experiments in-particular for the Compressed Baryonic Matter (CBM) experiment of FAIR facility at GSI, Germany.

nucl-th↗

arXiv2014

Facile preparation of agarose-chitosan hybrid materials and nanocomposite ionogels using an ionic liquid via dissolution, regeneration and sol-gel transition

We report simultaneous dissolution of agarose (AG) and chitosan (CH) in varying proportions in an ionic liquid (IL), 1-butyl-3-methylimidazolium chloride [C4mim][Cl]. Composite materials were constructed from AG-CH-IL solutions using the antisolvent methanol, and IL was recovered from the solutions. Composite materials could be uniformly decorated with silver oxide (Ag2O) nanoparticles (Ag NPs) to form nanocomposites in a single step by in situ synthesis of Ag NPs in AG-CH-IL sols, wherein the biopolymer moiety acted as both reducing and stabilizing agent. Cooling of Ag NPs-AG-CH-IL sols to room temperature resulted in high conductivity and high mechanical strength nanocomposite ionogels. The structure, stability and physiochemical properties of composite materials and nanocomposites were characterized by several analytical techniques, such as Fourier transform infrared (FTIR), CD spectroscopy, differential scanning colorimetric (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and scanning electron micrography (SEM). The result shows that composite materials have good thermal and conformational stability, compatibility and strong hydrogen bonding interactions between AG-CH complexes. Decoration of Ag NPs in composites and ionogels was confirmed by UV-Vis spectroscopy, SEM, TEM, EDAX and XRD. The mechanical and conducting properties of composite ionogels have been characterized by rheology and current-voltage measurements. Since Ag NPs show good antimicrobial activity, Ag NPs -AG-CH composite materials have the potential to be used in biotechnology and biomedical applications whereas nanocomposite ionogels will be suitable as precursors for applications such as quasi-solid dye sensitized solar cells, actuators, sensors or electrochromic displays.

physics.chem-ph↗

arXiv2014

Heavy Scalar, Vector and Axial-Vector Mesons in Hot and Dense Nuclear Medium

In this work we shall investigate the mass modifications of scalar mesons $\left( D_{0}, B_{0}\right)$,vector mesons $\left( D^{\ast}, B^{\ast}\right)$ and axial-vector mesons $\left(D_{1}, B_{1}\right)$ at finite density and temperature of the nuclear medium. The above mesons are modified in the nuclear medium through themodification of quark and gluon condensates. We shall find the medium modification of quark and gluon condensates within chiral SU(3) model through the medium modification of scalar-isoscalar fields $σ$ and $ζ$ at finite density and temperature. These medium modified quark and gluon condensates will further be used through QCD sum rules for the evaluation of in-medium properties of above mentioned scalar, vector and axial vector mesons. We shall also discuss the effects of density and temperature of the nuclear medium on the scattering lengths of above scalar, vector and axial-vector mesons. The study of the medium modifications of above mesons may be helpful for understanding their production rates in heavy-ion collision experiments. The results of present investigations of medium modifications of scalar, vector and axial-vector mesons at finite density and temperature can be verified in the Compressed Baryonic Matter (CBM) experiment of FAIR facility at GSI, Germany.

nucl-th↗

arXiv2013

Spin Dynamics in Graphene and Graphene like Nanocarbon Doped with Nitrogen the ESR Analysis

Nano engineered spin degree of freedom in carbon system may offer desired exchange coupling with optimum spin orbit interaction which is essential, to construct solid state qubits, for fault tolerant quantum computation. The purpose of this communication is to analyze spin dynamics of, basically, four types of systems, (i) Graphene (system with inversion symmetry), (ii) Graphene like nanocarbons (GNCs, broken inversion symmetry and heterostructure, sp2 and sp3, environment), and (iii) their nitrogen doped derivatives. The spin transport data was obtained using the electron spin resonance spectroscopy (ESR) technique, carried out over 123 to 473K temperature range. Analysis of shape, linewidths of dispersion derivatives,, and g factor anisotropy has been carried out. Spin parameters such as, spin spin relaxation time, spin lattice relaxation time, spin flip parameter,spin relaxation rate,spin, momentum relaxation rate,pseudo chemical potential, density of states, effective magnetic moment, spin concentration, defect concentration, and Pauli susceptibility, has been estimated, and examined for their temperature as well as interdependence. Details of the analysis are presented. The quantitative study underlined the following facts: (i) by and large, spin dynamics in Graphene and GNCs is significantly different, (ii) transport of spin behaves in opposite fashion, after doping nitrogen, in both the systems, (iii) reduction in the magnetization has been observed for both GNCs and Graphene, after doping nitrogen, (iv) hyperfine interactions have been observed in all classes of systems except in GNCs, (v) nitrogen doped GNCs seems to be appropriate for qubit designing.

physics.atm-clus↗

arXiv2011

D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter

We study the properties of $D$ and $\bar{D}$ mesons in hot isospin asymmetric strange hadronic matter, arising due to their interactions with the hadrons in the hyperonic medium. The interactions of $D$ and $\bar{D}$ mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). We also study the mass modifications of the charmonium states $J/ψ$, $ψ(3686)$ and $ψ(3770)$ in the isospin asymmetric strange hadronic matter at finite temperatures and investigate the possibility of the decay of the charmonium states into $D\bar D$ pairs in the hot hadronic medium. The mass modifications of these charmonium states arise due to their interaction with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within the effective chiral model. We also compute the partial decay widths of the charmonium states to the $D\bar {D}$ pairs in the hadronic medium. The strong dependence on density of the in-medium properties of the $D$, $\bar{D}$ and the charmonium states, as well as the partial decay widths of charmonium states to $D\bar {D}$ pairs, found in the present investigation, will be of direct relevance in observables like open charm enhancement as well as $J/ψ$ suppression in the compressed baryonic matter (CBM) experiments at the future Facility for Antiproton and Ion Research, GSI, where the baryonic matter at high densities is planned to be produced.

nucl-th↗

arXiv2010

D mesons in isospin asymmetric strange hadronic matter

We study the in-medium properties of $D$ and $\bar{D}$ mesons in isospin asymmetric hyperonic matter arising due to their interactions with the light hadrons. The interactions of $D$ and $\bar{D}$ mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). The nucleons, the scalar isoscalar meson, $σ$ and the scalar-isovector meson, $δ$ as modified in the strange hadronic matter, modify the masses of $D$ and $\bar{D}$ mesons. It is found that as compared to the $\bar{D}$ mesons, the $D$ meson properties are more sensitive to the isospin asymmetry at high densities. The effects of strangeness in the medium on the properties of $D$ and $\bar{D}$ mesons are studied in the present investigation. The $D$ mesons ($D^0$,$D^+$) are found to undergo larger medium modifications as compared to $\bar{D}$ mesons ($\bar {D^0}$, $D^-$) with the strangeness fraction, $f_s$ and these modifications are observed to be more appreciable at high densities. The present study of the in-medium properties of $D$ and $\bar{D}$ mesons will be of relevance for the experiments in the future Facility for Antiproton and Ion Research, GSI, where the baryonic matter at high densities will be produced. The isospin asymmetric effects in the doublet $D = (D^{0}, D^{+})$ in the strange hadronic matter should show in observables like their production and flow in asymmetric heavy-ion collisions as well as in $J/ψ$ suppression.

nucl-th↗