arXiv subjects

Jyoti Prasad Saha

Publications and source records attributed to Jyoti Prasad Saha.

At least 19 recordsLinked to original sources

arXiv2026

Issue of Branched Hamiltonian, Inflation and indispensability of scalar field in generalized Teleparallel theories

Generalized Teleparallel gravity theories were proposed as alternatives to the dark energy and modified theories of gravity. However, minimal generalization of TEGR and STEGR lead to the issue of branched Hamiltonian. Here, in the FLRW background we fix the coupling parameters of the said model in view of energy condition and show that the theory is free from the issue of Branched Hamiltonian unlike second-order Lanczos-Lovelock gravity. We also study scalar field driven inflation, which shows excellent agreement with recent observations. Nonetheless, a viable radiation era requires the very presence of the scalar field, which is retained at the late universe as dark energy. Thus the fundamental claim to act as an alternative to the dark energy is dubious.

gr-qc↗

arXiv2024

Impact of Vector like quarks on $(g-2)_μ$ with X-II-2HDM scenario and its phenomenological implications

The recent observation of the muon $(g-2)_μ$ anomaly continues to challenge the explanations provided by the Standard Model. However, this anomaly can potentially find reconciliation within the framework of two-Higgs doublet models, provided that the pseudoscalar mass remains low. The introduction of additional fermionic components, such as a generation of vector-like quarks, not only broadens the acceptable parameter range for elucidating the anomaly but also presents an opportunity to circumvent conflicts with constraints from B-decays and heavy Higgs searches. We demonstrate the efficacy of fitting the anomaly in the muon magnetic moment within these models, assuming that vector-like quarks do not undergo mixing with Standard Model quarks. With interactions following a type-X pattern for standard model quarks and a type-II pattern for vector-like quarks, results in models designated as type-XII2HDMVLQ. Additionally, we have explored double Higgs production within this model and observed when both the heavy Higgs and VLQ contribute the double Higgs production cross section significantly enhanced.

hep-ph↗

arXiv2023

Prospects of Gluino searches in multi-lepton channels in the light of ongoing LHC RUN-III

This study investigates the prospect of discovering strongly interacting gluinos in different multi-lepton channels with lepton multiplicity greater than or equal to 2 at LHC RUN-III, considering several pMSSM scenarios. The effectiveness of the Multivariate Analysis (MVA) method with the Boosted Decision Tree (BDT) algorithm is explored in order to obtain a better significance for different models. Promising results are obtained for the 3-lepton channels, indicating that the use of MVA methods can improve the sensitivity of the search for gluinos at LHC RUN-III. The study probes the multi-lepton signatures arising from gluinos via intermediate eweakinos and sleptons at an early stage of the LHC RUN-III. The heavier eweakinos can give rise to three or four lepton signals in which the squark hierarchy between L and R types plays a crucial role. The study considers two sets of benchmark points that satisfy all the collider constraints obtained from the LHC RUN-II data. Moreover, these sets of benchmark points are mostly consistent with WMAP/PLANCK data and the muon (g-2) constraint. The corresponding results from the MVA technique demonstrate that even for an integrated luminosity of 270 $fb^{-1}$, the 5 $σ$ discovery prospect of $3l+ jets + \cancel{E_T}$ for $M_{\widetilde{g}}=1.8$ TeV in the wino type model is promising. The study also presents the other various models that may show up at the early stage of LHC RUN-III. The wino type models in the scenario where left squarks are light and right squarks are heavy, exhibit the best prospect of discovering gluinos in the multi-lepton channels in the LHC RUN-III experiment. This paper's findings provide crucial insights into the potential discovery of gluinos in multi-lepton channels.

hep-ph↗

arXiv2023

Inflation and cosmological evolution with $F(R,G)$ gravity theory

In the last decade Planck PR4 data together with ground-based experimental data such as, BK18, BAO and CMB lensing, tightened constraint of the tensor to scalar ratio, starting form $r < 0.14$ to $r < 0.032$, while the spectral index lies within the range $0.9631 < n_s < 0.9705$. Viability of modified gravity theories, proposed as alternatives to the dark-energy issue, should therefore be tested in the light of such new result. Here, we explore $F(R,G)$ gravity theory in regard of the early universe and have shown that, it is not compatible with newly released constraints on $r$ and $n_s$ simultaneously. Further, it also fails to produce a feasible radiation dominated era. It therefore questions the justification of using the model for resolving the cosmic puzzle.

gr-qc↗

arXiv2023

Generalized Lewis-Riesenfeld invariance for dynamical effective mass in jammed granullar media under a potential well in non-commutative space

Consideration of the asteroid belt (Kuiper belt) as a jammed-granular media establishes a bridge between condensed matter physics and astrophysics. It opens up an experimental possibility to determine the deformation parameters for noncommutative space-time. Dynamics of the Kuiper belt can be simplified as dynamics of a dynamical effective mass for a jammed granular media under a gravitational well. Alongside, if one considers the space-time to be noncommutative, then an experimental model for the determination of the deformation parameters for noncommutative space-time can be done. The construction of eigenfunctions and invariance for this model is in general a tricky problem. We have utilized the Lewis-Riesenfeld invariant method to determine the invariance for this time-dependent quantum system. In this article, we have shown that a class of generalized time-dependent Lewis-Riesenfeld invariant operators exist for the system with dynamical effective mass in jammed granular media under a potential well in noncommutative space. To keep the discussion fairly general, we have considered both position-position and momentum-momentum noncommutativity. Since, up to a time-dependent phase-factor, the eigenfunctions of the invariant operator will satisfy the time-dependent Schrödinger equation for the time-dependent Hamiltonian of the system, the construction of the invariant operator fairly solve the problem mathematically, the results of which can be utilized to demonstrate an experiment.

physics.gen-ph↗

arXiv2022

Investigation of $(g-2)_μ$ anomaly in the $μ$-specific 2HDM with Vector like leptons and the phenomenological implications

The anomalous magnetic moment of muons has been a long-standing problem in SM. The current deviation of experimental value of the $(g-2)_μ$ from the standard model prediction is exactly $4.2σ$. Two Higgs Doublet Models can accommodate this discrepancy but such type of model naturally generate flavor changing neutral current(FCNC). To prevent this it was postulated that 2HDM without FCNC required that all fermions of a given charge couple to the same Higgs boson but the rule breaks in Muon Specific Two Higgs Doublet Model where all fermions except muon couple to one Higgs doublet and muon with the other Higgs doublet. The Muon Specific Two Higgs Doublet model explain muon anomaly with a fine tuning problem of very large $\tanβ$ value with other parameters. We have found a simple solution of this fine tuning problem by extending this model with a vector like lepton generation which could explain the muon anomaly at low $\tanβ$ value with a heavy pseudo scalar Higgs boson under the shadow of current experimental and theoretical constraints. Moreover, with the help of the cut based analysis and multivariate analysis methods, we have also attempted to shed some light on the potential experimental signature of vector lepton decay to the heavy Higgs boson in the LHC experiment. We have showed that a multivariate analysis can increase the vector like leptons signal significance by up to an order of magnitude than that of a cut based analysis.

hep-ph↗

arXiv2022

Mutual information, islands in black holes and the Page curve

The role played by the mutual information of subsystems on the Page curve is explored in this paper. With the total system consisting of the black hole and radiation, together with the inclusion of island, we observe that the vanishing of mutual information between $B_+$ and $B_-$ which in turn means the disconnected phase of the entanglement wedge corresponding to $B_+\cup B_-$, yields a time scale of the order of scrambling time. This results in a time independent expression for the fine grained entropy of Hawking radiation consistent with the correct Page curve. We also find corrections to this entropy and Page time which are logarithmic and inverse power law in form.

hep-th↗

arXiv2020

Generalized entanglement temperature and entanglement Smarr relation

We observe that in presence of excitation, a thermodynamic Smarr like relation corresponding to a generalized entanglement temperature ($T_g$) can be holographically obtained for the entanglement entropy of a subsystem. Such a relation emerges naturally by demanding that the generalized entanglement temperature produces the exact Hawking temperature as the leading term in the IR limit ($l\rightarrow \infty$). Remarkably, this relation has the same form as the Smarr relation in black hole thermodynamics. We demonstrate this for three spacetime geometries, namely, a background with a nonconformal factor, a hyperscaling violating geometry background, and a charged black hole background which corresponds to a field theory with a finite chemical potential.

hep-th↗

arXiv2020

Squeezed coherent states for gravitational well in noncommutative space

Gravitational well is a widely used system for the verification of the quantum weak equivalence principle (WEP). We have studied the quantum gravitational well (GW) under the shed of noncommutative (NC) space so that the results can be utilized for testing the validity of WEP in NC-space. To keep our study widely usable, we have considered both position-position and momentum-momentum noncommutativity. Since coherent state (CS) structure provides a natural bridging between the classical and quantum domain descriptions, the quantum domain validity of purely classical phenomena like free-fall under gravity might be verified with the help of CS. We have constructed CS with the aid of a Lewis-Riesenfeld phase space invariant operator. From the uncertainty relations deduced from the expectation values of the observables, we have shown that the solutions of the time-dependent Schrödinger equation are squeezed-coherent states.

quant-ph↗

arXiv2020

Constraints on the choice of position dependent effective mass and external potential for the existence of Lewis-Riesenfeld invariance and quantum canonical transformation

Lewis-Riesenfeld -Ermakov's (LR) invariant method for the construction of time-dependent phase-space invariant is extended for the general quantum system with position-dependent effective mass (PDEM) Hamiltonian. It turns out that, only a specific class of PDEM and a particular class of external potentials will exhibit the LR-invariant operator in close form. Then we have determined a class of unitary time-dependent quantum canonical transformation for the concerned PDEM and external potentials so that an equivalent time-independent PDEM Hamiltonian is obtained.

quant-ph↗

arXiv2020

Double Higgs boson production as an exclusive probe for a sequential fourth generation with wrong-sign Yukawa couplings

It has been shown that the data from the Large Hadron Collider (LHC) does not rule out a chiral sequential fourth generation of fermions that obtain their masses through an identical mechanism as the other three generations do. However, this is possible only if the scalar sector of the Standard Model is suitably enhanced, like embedding it in a type-II two-Higgs doublet model. In this article, we try to show that double Higgs production (DHP) can unveil the existence of such a hidden fourth generation in a very efficient way. While the DHP cross-section in the SM is quite small, it is significantly enhanced with a fourth generation. We perform a detailed analysis of the dependence of the DHP cross-section on the model parameters, and show that either a positive signal of DHP is seen in the early next run of the LHC, or the model is ruled out.

hep-ph↗

arXiv2019

Holographic entanglement entropy and generalized entanglement temperature

In this work we study the flow of holographic entanglement entropy in dimensions $d \geq 3$ in the gauge/gravity duality set up. We observe that a generalized entanglement temperature $T_g$ can be defined which gives the Hawking temperature $T_H$ in the infrared region and leads to a generalized thermodynamics like law $E= \left(\frac{d-1}{d}\right)T_g~S_{REE}$, which becomes an exact relation in the entire region of the subsystem size $l$, including both the infrared ($l\rightarrow\infty$) as well as the ultraviolet ($l\rightarrow 0$) regions. Furthermore, in the IR limit, $T_g$ produces the Hawking temperature $T_H$ along with some correction terms which bears the signature of short distance correlations along the entangling surface. Moreover, for $d\geq 3$, the IR limit of the renormalized holographic entanglement entropy gives the thermal entropy of the black hole as the leading term, however, does not have a logarithmic correction to the leading term unlike the BTZ black hole ($d=2$) case. The generalized entanglement temperature $T_g$ also firmly captures the quantum mechanical to thermal crossover in the dual field theory at a critical value $l_c$ of the subsystem size in the boundary which we graphically represent for $AdS_{3+1}$ and $AdS_{4+1}$ black holes. We observe that this critical value $l_c$ where the crossover takes place decreases with increase in the dimension of the spacetime.

hep-th↗

arXiv2019

On the position dependent effective mass Hamiltonian

Noncommutivity of position and momentum makes it difficult to formulate the unambiguous structure of the kinetic part of Hamiltonian for the position-dependent effective mass (PDEM). Various existing proposals of writing the viable kinetic part of the Hamiltonian for PDEM, conceptually lack from first principle calculation. Starting from the first principle calculation, in this article, we have advocated the proper self-adjoint form of the kinetic part of Hamiltonian for PDEM. We have proposed that ambiguity of construction of viable kinetic part for PDEM can be avoided if one takes the care from the Classical level combination of position and momentum. \\ In the quantum level, the spatial points do not appear in equivalent footing for the measure of inertia (mass). This exhibits the existence of an inertia potential. Thus the new structure of the Kinetic part differs from the existing structure of the kinetic part of Hamiltonian by providing an extra potential like contribution. This inertia potential can be absorbed with the external potential and redefine the known structure of PDEM under this effective potential. This enables us to apply the existing formalism of quantum mechanics. The coherent state structures for the newly proposed form of Hamiltonian are provided for a few simple experimentally important models.

physics.gen-ph↗

arXiv2017

Self-adjoint extension for Maxwell-Chern-Simons model in long wavelength limit

In the long wavelength limit, Maxwell-Chern-Simmon model and the dynamics of a particle in a plane under an external magnetic field perpendicular to that plane are identical. The self adjoint extension of such a problem depends on the value of angular momentum quantum number $l$. In this article, we have shown that for $l\neq 0$, the operator describing the Landau level wave-function is self adjoint; whereas, for $l=0$, infinite number of self-adjoint extension by an one parameter unitary mapping is possible.

hep-th↗

arXiv2014

Modified Hamiltonian formalism for Regge Teitelboim Cosmology

The Ostrogradski approach for the Hamiltonian formalism of higher derivative theory is not satisfactory because of the reason that the Lagrangian cannot be viewed as a function on the tangent bundle to coordinate manifold. In this article, we have used an alternative approach which leads directly to the Lagrangian which, being a function on the tangent manifold, gives correct equation of motion; no new coordinate variables need to be added. This approach can be directly used to the singular (in Ostrogradski sense) Lagrangian. We have used this method for the Regge Teitelboim (RT) minisuperspace cosmological model. We have obtained the Hamiltonian of the dynamical equation of the scale factor of RT model.

hep-th↗

arXiv2014

Current conservation in charge conjugation parity time reversal symmetry (CPT) violating gauge-invariant nonlocal Thirring model

Charge conjugation, parity transformation and time reversal symmetry (CPT) violation and Lorentz invariance can coexist in the framework of non-local field theory. In this article we have proposed a class of Charge conjugation, parity transformation and time reversal symmetry (CPT) violating Lorentz invariant nonlocal gauge-invariant models, which can be termed as non-local Thirring models. The conserved currents in this aspect are obtained.

hep-th↗

arXiv2014

A complete determination of New Physics parameters in leptonic decays of $\mathbf{B_{s}^0}$

Recently LHCb has measured the branching ratio of the rare decay of $B_s^0\rightarrow μ^+ μ^- $ as $2.9^{+1.1}_{-1.0} \times10^{-9}$ which is at par with the predicted standard model (SM) value. This result does not predict the absence of new physics (NP), rather it confines the NP parameter-space in a more stringent fashion. In this paper we have used the general loop level Hamiltonian to constrain the parameter space for the NP couplings for $B_s^0\rightarrow μ^+ μ^- $ from the experimental branching ratio. Using the available parameter space for these couplings, we have explored the angular analysis of the cascade decay of $B^0_{s}\to τ^+τ^- \to (ρ^+\barν_τ)_{τ^+}(π^{-}ν_τ)_{τ^-} \to ((π^+ π^0)_{ρ^+}\barν_τ)_{τ^+}(π^{-}ν_τ)_{τ^-}$. This analysis shows presence of NP can be identified by the angular analysis and also shows how to isolate the NP contribution from the SM. We believe that in future with the reduced error in the branching ratio measurement and better $τ$ cone reconstruction technique we will be able to probe NP signal using this angular analysis.

hep-ph↗

arXiv2013

Lorentz Invariant CPT Violation for a Class of Nonlocal Thirring Model

It is possible to construct Lorentz invariant CPT violating models for Nonlocal Quantum Field Theory. In this article, we present a class of Nonlocal Thirring Models, in which the CPT invariance is violated while the Lorentz invariance is present. As a result, in certain cases the mass-splitting between particle and antiparticle are identified.

hep-th↗