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Rituparna Ghosh

Publications and source records attributed to Rituparna Ghosh.

8 recordsLinked to original sources
arXiv2026

Hunting long-lived doubly charged scalars at the HL-LHC

This work studies the collider phenomenology of long-lived doubly charged scalars. After reviewing the existing searches for the doubly charged scalar in both the prompt and the long-lived regimes, we identify an intermediate range of proper decay length, namely, $\mathcal{O}(0.1~\mathrm{mm}) \lesssim c\tau \lesssim \mathcal{O}(100~\mathrm{mm})$, where conventional searches lose sensitivity. We investigate the prospects for probing the doubly charged scalar both in the presence and in the absence of the $\Delta L=2$ Yukawa coupling of the $SU(2)_{L}$ complex triplet. In the presence of this coupling, $H^{\pm\pm}$ can be long-lived only for masses in the range $100$-$150~\mathrm{GeV}$, whereas in the fermiophobic scenario (i.e., in the absence of the $\Delta L=2$ coupling), the range extends to $\mathrm{TeV}$ scale. We propose a displaced-vertex search at the HL-LHC for doubly charged scalars with masses up to $\approx 1~\mathrm{TeV}$ and $c\tau=10$-$100~\mathrm{mm}$ in the fermiophobic scenario, while a benchmark point with a doubly charged scalar of mass $120~\mathrm{GeV}$ and $c\tau = 5~\mathrm{mm}$ is considered when the complex triplet scalar couples to leptons. We show that a cut on the invariant mass of the displaced vertex as reconstructed from the associated tracks can strongly suppress Standard Model backgrounds. We present projected limits on the Drell-Yan pair-production cross section for the doubly charged scalar at $\sqrt{s}=14~\mathrm{TeV}$ with an integrated luminosity of $3000~\mathrm{fb}^{-1}$, considering two illustrative assumptions for the residual background. Displaced-vertex searches thus probe a region complementary to those covered by prompt and heavy stable charged-particle searches.

hep-ph↗
arXiv2025

Diphoton signals for the Georgi-Machacek scenario at the Large Hadron Collider

The diphoton channel for exploring the Georgi-Machacek (GM) scenario containing scalar triplets at the Large Hadron Collider (LHC) has been identified as germane, and subjected to a detailed study. The scalar spectrum of the model, which imposes a custodial SU(2) on the potential, gets classified into a 5-plet, a 3-plet and two singlets under the custodial symmetry. While most attempts to probe or constrain the scenario at the LHC depend largely on signals of charged scalars, we point out that the custodial SU(2) singlet state H can have a substantial branching ratio (amounting to a few percent) into two photons. We carry out a detailed simulation of the resulting signal and the standard model backgrounds, obtaining the signal significance in different regions of the parameter space using the profile likelihood ratio method. Substantial regions of the GM parameter space is thus shown to be accessible to LHC studies, both at the high-luminosity run with $\int {\cal L} dt = 3000 fb^{-1}$, and also in Run-3 with $\int {\cal L} dt = 300 fb^{-1}$, even after folding in systematic errors. We have also demonstrated that a rather subtantial improvement in the signal significance is achieved by switching over from a cut-based analysis to one based on neural network.

hep-ph↗
arXiv2025

Leptogenesis with triplet scalars at electroweak scale

Up until now the works regarding leptogenesis have discussed different mechanisms to explain the observed baryon asymmetry of the universe (BAU). The type-$II$ seesaw mechanism employing triplet scalars has been well studied in this context and the triplet vacuum expectation value (VEV) answering to the observed BAU is $(< 10^{-2} ~ GeV)$. On the contrary we are invoking an extended Georgi-Machacek type scenario, capable of generating BAU through leptogenesis while keeping the triplet VEV at a moderate range where it plays a nontrivial role in electroweak symmetry breaking (EWSB). In this study we have also considered the decaying scalar mass responsible for leptogenesis to be within a TeV and hence one can probe this possibility at the Large Hadron Collider (LHC) itself via different kinds of signature corresponding to different triplet VEV region.

hep-ph↗
arXiv2023

The strong b-lattice of quasi skew-rings

This paper gives the relation between quasi completely inverse semirings and strongly additively quasi completely inverse semirings and generates the necessary and sufficient conditions for a strongly additively quasi completely inverse semiring to be a strong b-lattice of quasi skew-rings.

math.RA↗
arXiv2023

The $ρ$ parameter and the CDF W-mass anomaly: observations on the role of scalar triplets

The $ρ$-parameter, together with the W-and Z-masses, acts as Occam's razor on extensions of the electroweak symmetry breaking sectors. We apply this to non-doublet Higgs scenarios, by examining the CDF- $II$ claim on the W-boson mass. Suspending any judgement on the CDF claim, we show that in general, if one works at the tree level, theoretical models which predict $ρ=1$ at the tree-level are inconsistent with the CDF claims at 4-6 standard deviations if one confines oneself to the existing Z-boson mass, and the earlier $M_W$ value from either the global fit or the ATLAS data. We take some well-motivated scenarios containing one or more scalar SU(2) triplets in addition to the usual doublet, and show that, both a scenario including a complex scalar triplet and one with a complex as well as a real triplet (the Georgi-Machacek model) can be made consistent with the new data, where a small splitting between the complex and the real triplet vacuum expectation values is required in the second scenario. We will explore the consequences of this splitting, either at tree level or via incalculable new physics contribution to $M_W$, and indicate, as illustrations its implications in $H^{\pm}W^{\mp}Z$ type interaction vertices.

hep-ph↗
arXiv2023

Some new observations for the Georgi-Machacek scenario with triplet Higgs

The Georgi-Machacek model, introducing a complex and a real scalar triplet as additional components of the electroweak symmetry breaking sector, enables substantial triplet contributions to the weak gauge boson masses, subject to the equality of the complex and the real triplet vacuum expectation values (vev) via a custodial SU(2) symmetry. We present an updated set of constraints on this scenario, from collider data (including those from 137/139~fb$^{-1}$ of luminosity at the Large Hadron Collider), available data on the 125-GeV scalar, indirect limits and also theoretical restrictions from vacuum stability and unitarity. It is found that some bounds get relaxed, and the phenomenological potential of the scenario is more diverse, if the doubly charged scalar in the spectrum can decay not only into two like-sign $W$'s but also into one or two singly charged scalars. Other interesting features are noticed in a general approach, such as substantial $γγ$ and $Zγ$ branching ratios of the additional custodial singlet scalar, and appreciable strength of the trilinear interaction of a charged scalar, the $W$ and the $Z$. Finally,, we take into account the possibility of custodial SU(2) breaking, resulting in inequality of the real and the complex scalar vevs which too in principle may allow large triplet contribution to weak boson masses. Illustrative numerical results on the modified limits and predictions are presented, once more taking into account all the constraints mentioned above.

hep-ph↗
arXiv2013

Scattering of Carriers by Charged Dislocations in Semiconductors

The scattering of carriers by charged dislocations in semiconductors is studied within the framework of the linearized Boltzmann transport theory with an emphasis on examining consequences of the extreme anisotropy of the scattering potential. A new closed-form approximate expression for the carrier mobility valid for all temperatures is proposed. The ratios of quantum and transport scattering times are evaluated after averaging over the anisotropy in the relaxation time. The value of the Hall scattering factor computed for charged dislocation scattering indicates that there may be a factor of two error in the experimental mobility estimates using the Hall data. An expression for the resistivity tensor when the dislocations are tilted with respect to the plane of transport is derived. Finally an expression for the isotropic relaxation time is derived when the dislocations are located within the sample with a uniform angular distribution.

cond-mat.dis-nn↗