arXiv subjects

A. Mukherjee

Publications and source records attributed to A. Mukherjee.

At least 19 recordsLinked to original sources

arXiv2026

Regularity of core coupled high-spin structure in neutron-rich $^{196-202}$Au isotopes approaching N $=126$

Excited states built upon long-lived high-spin isomers in hard-to-reach neutron-rich Au ($Z=79$) isotopes were populated using multi-nucleon transfer reactions between $^{136}$Xe and $^{198}$Pt at 7 MeV/u. These states in $^{196,\,198-202}$Au were identified for the first time using the powerful combination of the VAMOS++ spectrometer, the CATLIFE detection system, and the AGATA $γ$-ray tracking array. Their measured energies exhibit remarkable regularity as a function of neutron number and are seen to be inherited from the energies of yrast-band members in the corresponding Hg ($Z=80$) isotope. Large-scale shell-model calculations reproduce the observed regularity and show that these states arise from the unique-parity orbitals $\pi0h_{11/2}$ and $\nu0i_{13/2}$ coupled to the Hg core. This regularity is due to the dominant proton configurations of the Hg and Au isotopes, where the level energies are almost independent of different neutron-orbital occupancies. The calculated Au wave functions show significant higher-spin components of the corresponding Hg core, unlike what is expected in the conventional interpretation in terms of the weak-coupling/decoupling limits of the particle-core coupling model.

nucl-ex↗

arXiv2026

Evolution of high-spin states in neutron-rich $^{195-202}$Au isotopes approaching the $N=126$ shell closure

\textbf{Background: } The nuclear structure in the region southwest of the doubly magic $^{208}$Pb is important to benchmark theoretical models relevant for neutron-rich heavy element formation and for the origin of the $A\approx195$ peak in the mass abundance distribution. Although neutron-rich Pb, Tl, and Hg ($Z=80-82$) isotopes are relatively well studied, experimental data for neutron-rich Au isotopes ($Z=79$) remain largely limited due to experimental challenges. \textbf{Purpose: } The purpose of this work is to investigate the evolution of the high-spin structure in neutron-rich Au isotopes near the $N=126$ shell closure and to characterize the underlying shell-model configurations, with a particular focus on the roles of the high-$j$ unique-parity $πh_{11/2}$ and $νi_{13/2}$ orbitals. \textbf{Methods: } Neutron-rich $^{195-202}$Au isotopes were produced using multi-nucleon transfer reactions of $^{198}$Pt($^{136}$Xe, $^{x}$I)$^{y}$Au at a beam energy of 7 MeV/u. %between a 7 MeV/u $^{136}$Xe beam and a $^{198}$Pt target at GANIL. Prompt and delayed $γ$-ray spectroscopy of isotopically identified reaction products was performed with a unique experimental setup combining the VAMOS++ large acceptance magnetic spectrometer, the AGATA HPGe $γ$-ray tracking array, and the CATLIFE detection system.

nucl-ex↗

arXiv2026

$π$-QCD; Proposal for Experiments at the GSI Pion Beam Facility

We propose to investigate the dynamics of hadronic matter in the strong QCD regime using the pion-beam facility at GSI in conjunction with HADES. This program will study hadron physics through elementary pion-nucleon interactions up to $\sqrt{s}\approx$2.35 GeV, bridging cold matter research with detailed analyses of exclusive reactions. Our goals include exploring baryon resonance formation and their electromagnetic structures. This will complement photo-production experiments (e.g., ELSA) and enhance our understanding of emissivity in dense, hot hadronic matter. Key topics include examining baryon couplings to mesons and virtual photons, analyzing hyperon weak decays in exclusive reactions, and using Partial Wave Analyses with differential cross sections and polarization observables to achieve unprecedented precision in baryon-meson coupling data ($ρ$N, $ω$N). Furthermore, e$^{+}$e$^{-}$ production measurements off nucleons will provide insight into the electromagnetic transition form factors of baryons in the time-like region, revealing the role of vector mesons ($ρ$, $ω$). Reactions on nuclear targets allow for detailed studies of hadron properties, including vector-meson line shapes and strengths in cold nuclear matter. These measurements provide a critical reference for the interpretation of results from the hot and dense environment created in $A+A$ collisions. This research also has broader implications. It will contribute to the modeling of neutrino-nucleus interactions, facilitate unprecedented investigations into hypernuclei formation, and enhance our understanding of strong interaction dynamics across different energy regimes.

nucl-ex↗

arXiv2026

Measurement of Differential Cross Sections and Integrated Luminosity using Proton-Proton Elastic Scattering with HADES at T = 4.53 GeV and T = 1.60 GeV

This work presents an investigation of elastic proton-proton scattering based on data collected with the recently upgraded HADES detector using beams of protons with kinetic energies of $T = 4.53$ GeV and $T = 1.60$ GeV impinging on a liquid hydrogen target. This is the first measurement emerging from the upgraded detector setup, including a Forward Detector with straw-tube tracking planes designed for the PANDA experiment. The well-constrained two-body kinematic relations of elastic scattering have been exploited to study the detector alignment, the beam alignment, and to provide the final measurement of the beam energy. In addition, the recorded luminosity of the experiment has been determined by normalizing the HADES data in a range of the squared four-momentum transfer $t$ that overlaps with measurements by previous experiments worldwide. Furthermore, the differential cross sections have been determined over a large range of $t$ from which the slope parameter $B$ is extracted, yielding $B = 8.98 \pm 0.3$ (GeV/$c$)$^{-2}$ and $7.3 \pm 0.1$ (GeV/$c$)$^{-2}$ at $T = 4.53$ GeV and $1.60$ GeV, respectively. This contribution to the world database on elastic proton-proton scattering provides input to theoretical modeling and serves as a reference for luminosity determinations by future experiments in the same energy range.

hep-ex↗

arXiv2025

Relaxation Dynamics in Atomic-Molecular Bose Condensates in the Presence of Gaussian Noise

We investigate the dynamics of atomic and molecular bosons weakly coupled via Feshbach detuning in the presence of Gaussian white noise. The time-evolution of the population imbalance between the two species, as well as the coherence of the system are analyzed using a Bloch sphere model. We observe that the system exhibits relaxation of the Bloch vector components towards a stable equilibrium. In the population imbalance dynamics, the relaxation rates predicted by the Bogoliubov Born Green Kirkwood Yvon (BBGKY) hierarchy are found to be smaller than those calculated with a simple the mean field approximation. As for the coherence dynamics, the inclusion of correlations and fluctuations in the system can either increase or decrease the relaxation time, depending on the initial conditions. We attribute the increase in the relaxation time to the emergence of a structured noise, and the subsequent suppression of certain dephasing channels. We also study the impact of correlations and fluctuations on time-averaged quantities like the drift speed, the fringe visibility, the phase entanglement etc., and find the results to be in perfect agreement with the properties of the relaxation dynamics.

cond-mat.quant-gas↗

arXiv2025

Unravelling the Antimicrobial Action Mechanism of Ribosomal Protein S30

Ribosomal protein S30 (RS30) exhibits potent antimicrobial activity against a broad spectrum of bacteria. Despite its efficacy, the underlying action mechanism remained elusive. In this study, we unravel the fundamental mechanism by which RS30 exerts its bactericidal effects, using a combination of microbiological assays and advanced biophysical techniques. Microbiological analyses reveal that RS30 kills bacteria primarily through membrane depolarization, despite limited membrane permeabilization, indicating an unconventional mode of action involving no or partial lysis of the membrane. Importantly, RS30 demonstrates time-dependent bactericidal activity with no detectable cytotoxicity toward mammalian cells, underscoring its high selectivity. This selective action was further confirmed using biophysical experiments on model membrane systems composed of anionic (bacterial mimic) and zwitterionic (mammalian mimic) phospholipids. Our measurements suggested that RS30 preferentially binds to anionic membranes via electrostatic interactions, undergoes a conformational transition from a random coil to an α-helix upon binding, and induces vesicle aggregation. Quasielastic neutron scattering (QENS) measurements provide microscopic insights, showing that RS30 significantly restricts the lateral diffusion of anionic lipids, thereby perturbing membrane dynamics and increasing susceptibility to external stress. Together, our findings uncover important insights into the antimicrobial action mechanism of RS30, characterized by selective membrane interaction, structural transformation, and dynamic modulation of lipid membranes.

cond-mat.soft↗

arXiv2024

Existance of octupole correlation in 116Sn

The negative parity states in 116Sn have been investigated in terms of octupole correlation. The same is probed by using the Indian National Gamma Array (INGA) facility at Variable Energy Cyclotron Centre, Kolkata using the reaction, 114Cd(α,2n) 116Sn at 34 MeV energy. Three new γ-transitions relevant to the present investigation are reported and the spin-parities of the associated levels are assigned based on the DCO-ratios and polarisation measurements. The interband transitions between the positive parity ground band and the negative parity band are newly observed and the corresponding extracted ratio of transition probability, B(E1)/B(E2) indicated the existence of octupole correlation in these nuclei. The enhanced transition rates for E1 and E3 transitions between these opposite parity bands and corroboration of soft octupole deformation ultimately aid the onset of octupole excitation in this isotope.

nucl-ex↗

arXiv2023

Correspondence between Dicke-model semiclasscial dynamics in the superradiant dipolar phase and the Euler heavy top

Analytic expression is found for the frequency dependence of transmission coefficient of a transmission line inductively coupled to the microwave cavity with superradiant condensate. Sharp transmission drops reflect condensate's frequencies spectrum. These results pave way to direct detection of emergence of the superradiant condensates in quantum metamaterials. Results are based on the analytic solutions of the nonlinear semiclassical dynamics of superradiant photonic condensate in the Dicke model of an ensemble of two-level atoms dipolar coupled to the electromagnetic field in the microwave cavity. In adiabatic limit with respect to photon degree of freedom the system is approximately integrable, with evolution being expressed via Jacobi elliptic functions of real time. Depending on the coupling strength, the semiclassical coordinate of superradiant condensate in the ground state either oscillates in one of the two degenerate minima of condensate's potential energy or traverses between them over the saddle point. An experimental setup for measuring of the breakdown of the normal phase of the Dicke model via coupling to the transmission line is proposed. A one-to-one mapping of semiclassical motion of superradiant condensate on the nodding of unstable Lagrange "sleeping top" also turns Dicke model into analogue device for modelling dynamics of mechanical systems.

physics.optics↗

arXiv2023

Dicke model semiclassical dynamics in superradiant dipolar phase in the 'bound luminosity' state

Analytic solution of semiclassical dynamics equations of the Dicke model in a superradiant state is presented. The time dependences of the amplitudes of superradiant bosonic condensate and coherent two-level atomic array in the microwave cavity prove to be expressed via Jacobi elliptic functions of real time and manifest existence of an adiabatic invariant of motion in the strongly coupled system. The periodic beatings of the photonic and atomic coherent state amplitudes are shifted in time revealing an effect of 'bound luminosity', when energy stored in the two-level system during 'darkness' in the cavity is suddenly converted into photonic condensate that 'illuminates' the cavity for half a period, before it plunges into 'darkness' again.

quant-ph↗

arXiv2023

Workshop on a future muon program at FNAL

The Snowmass report on rare processes and precision measurements recommended Mu2e-II and a next generation muon facility at Fermilab (Advanced Muon Facility) as priorities for the frontier. The Workshop on a future muon program at FNAL was held in March 2023 to discuss design studies for Mu2e-II, organizing efforts for the next generation muon facility, and identify synergies with other efforts (e.g., muon collider). Topics included high-power targetry, status of R&D for Mu2e-II, development of compressor rings, FFA and concepts for muon experiments (conversion, decays, muonium and other opportunities) at AMF. This document summarizes the workshop discussions with a focus on future R&D tasks needed to realize these concepts.

hep-ex↗

arXiv2023

Calculation of true coincidence summing correction factor for clover detector in add-back and direct mode

The true coincidence summing effect on the full-energy peak efficiency calibration of an unsuppressed clover HPGe detector has been studied. Standard multi-energetic and mono-energetic gamma-ray sources were used to determine the full-energy peak efficiency of the detector as a function of the gamma-ray energies at different source-to-detector distances. The true coincidence summing correction factors for the full-energy peak efficiency of the detector has been determined, in the add-back and direct modes of the detector, using both experimental and analytical methods. Geant4 simulations were performed to obtain the full-energy peak efficiency and total efficiency of the detector for different gamma-ray energies. The simulated efficiencies were used to calculate the correction factors using the analytical method. The correction factors obtained from both analytical and experimental methods were found to be in good agreement with each other. The clover detector in add-back mode exhibits larger summing corrections compared to the direct mode for the same source-to-detector distances. For the add-back mode, the coincidence summing effect is not significant for source-to-detector distances ~ 13 cm or above, whereas, for the direct mode, measurements can be performed for source-to-detector distances ~ 5 cm or above without considering the coincidence summing effect.

physics.ins-det↗

arXiv2023

Calculation of true coincidence summing correction factor for a Broad Energy Germanium (BEGe) detector using standard and fabricated sources

The true coincidence summing (TCS) correction factor for a Broad Energy Germanium (BEGe) detector has been calculated at far and close geometry measurement using multi-energetic radioactive $γ$-ray sources $^{60}$Co, $^{133}$Ba and $^{152}$Eu. The correction factors were calculated using experimental method and analytical method. Photopeak efficiency and total efficiency required to calculate the correction factor were obtained using Geant4 Monte Carlo simulation code. A few standard as well as fabricated mono-energetic sources were also included in the $γ$-ray efficiency measurements. The simulated efficiencies of mono-energetic $γ$-ray sources were matched to experimental $γ$-ray efficiencies by optimizing the detector parameters. The same parameters were used to obtain the photopeak and total efficiency for $γ$-ray of our interest and coincident $γ$-ray. Analytical correction factors and experimental correction factors were found in good agreement with each other.

physics.ins-det↗

arXiv2022

Systematic investigation of channel coupling effects on elastic, inelastic and neutron transfer channels in $^6$Li+$^{159}$Tb

Elastic scattering angular distribution for weakly bound nucleus $^{6}$Li on the deformed rare earth $^{159}$Tb target nucleus has been measured at energies around the Coulomb barrier. The elastic scattering cross sections for this reaction consist of inelastic contributions from low lying excited states of $^{159}$Tb. The pure elastic cross-sections have been extracted from the admixture of elastic and inelastic data. The optical model potential parameters for the system have been obtained from the extracted pure elastic scattering cross sections. Coupled channel calculations have been performed with this set of potential parameters, to compare the theoretical and experimental inelastic scattering cross sections. The work has been extended to obtain the spectroscopic factor for $^{158}$Tb+n configuration from the experimental 1n-pickup data.

nucl-ex↗

arXiv2022

Gluon TMDs and inelastic $J/ψ$ leptoproduction at the EIC

We study the Sivers azimuthal asymmetry for $J/ψ$ production in semi-inclusive deep inelastic scattering, and the still poorly known gluon Sivers function. We concentrate on the $J/ψ$ low transverse momentum region, employing the transverse-momentum dependent generalised parton model (GPM), and its colour gauge invariant extension (CGI-GPM), which includes final-state interactions at leading order. We adopt the nonrelativistic QCD (NRQCD) framework for the quarkonium formation mechanism, and compare our results for the unpolarised cross section and the Sivers asymmetry with available data, respectively from HERA and COMPASS. Finally, we give estimates for the asymmetry in the kinematical regime of the future Electron-Ion Collider (EIC).

hep-ph↗

arXiv2021

Fusion of 16O+165Ho at deep sub-barrier energies

Fusion cross-sections have been measured for the asymmetric system 16O+165Ho at energies near and deep below the Coulomb barrier with an aim to investigate the occurrence of fusion hindrance for the system. Fusion cross sections down to ~ 700 nb have been measured using the off-beam gamma-ray technique. The fusion cross sections have been compared with the coupled channel calculations. Although the onset of fusion hindrance could not be observed experimentally, an indication of a small deviation of the experimental fusion cross-sections with respect to the calculated cross-sections could be observed at the lowest energy measured. However, the energy onset of fusion hindrance has been obtained from the extrapolation technique and is found to be about 2 MeV below the lowest energy of the present measurement.

nucl-ex↗

arXiv2021

Large back-angle quasielastic scattering for $^{7}$Li+$^{159}$Tb

Quasielastic scattering excitation function at large backward angle has been measured for the weakly bound system, $^{7}$Li+$^{159}$Tb at energies around the Coulomb barrier. The corresponding quasielastic barrier distribution has been derived from the excitation function, both including and excluding the $α$-particles produced in the reaction. The centroid of the barrier distribution obtained after inclusion of $α$-particles was found to be shifted higher in energy, compared to the distribution excluding the $α$-particles. The quasielastic data, excluding the $α$-particles, have been analyzed in the framework of continuum discretized coupled channel calculations. The quasielastic barrier distribution for $^{7}$Li+$^{159}$Tb, has also been compared with the fusion barrier distribution for the system.

nucl-ex↗

arXiv2020

Dynamical study of nonlinear ion-acoustic waves in presence of charged space debris at Low Earth Orbital (LEO) plasma region

We consider the nonlinear ion-acoustic wave induced by the orbiting charged space debris in the plasma environment generated at Low Earth Orbital (LEO) region. The generated nonlinear ion-acoustic wave is shown to be governed by the forced Korteweg-de Vries equation with the forcing function dependent on the charged space debris function. For a specific relationship between the forcing debris function and the nonlinear ion-acoustic wave, the forced KdV equation turns to be a completely integrable system where the debris function obeys a definite non-holonomic constraint. A special exact accelerated soliton solution (velocity of the soliton changes over time whereas its amplitude remains constant) has been derived for the ion-acoustic wave for the first time. On the other hand, the amplitude of the solitonic debris function varies with time, and its shape changes during propagation. Approximate ion-acoustic solitary wave solutions with time-varying amplitude and velocity, have been derived for different weak localized charged debris functions. Possible applications of the obtained results in space plasma physics are stated along with future the direction of research.

nlin.PS↗

arXiv2020

On the extraction of the valence transversity distributions from SIDIS data

The transversity distribution for $u$ and $d$ quarks is usually extracted from data on spin asymmetries in Semi Inclusive Deep Inelastic Scattering (SIDIS): however, due to its chiral odd nature, it has to be coupled to another chiral odd function, typically the Collins or the di-hadron fragmentation function. A recent suggestion of considering SIDIS data involving ratios of spin asymmetries and avoiding a knowledge of the Collins function, is briefly discussed. New measurements, involving ratios of cross sections, are suggested. They would allow a direct extraction of the transversity ratio, $h_1^{d_V}/h_1^{u_V}$. Numerical estimates are given.

hep-ph↗