arXiv subjects

R. Benbrik

Publications and source records attributed to R. Benbrik.

At least 37 records · Page 2Linked to original sources

arXiv2021

Laser-assisted CP-odd and CP-even Higgs bosons production in THDM

In this paper, we have theoretically studied the neutral Higgs pair production in Two Higgs Doublet Model (THDM) in the presence of a circularly polarized laser field. The laser-assisted differential partial cross section is derived in the centre of mass frame at the leading order including $Z$ diagram. The total cross section is computed numerically by integrating the differential cross section over the solid angle $dΩ$. Two benchmark points are discussed for the THDM parameters. In the first step, we have analyzed the total cross section of ${e}^{+}{e}^{-}\rightarrow h^{0}A^{0}$ by considering $H^{0}$ as the standard model-like Higgs boson. Then, the process ${e}^{+}{e}^{-}\rightarrow H^{0}A^{0}$ is studied by taking $h^{0}$ as the Higgs boson of the standard model. For both benchmark points, the laser-assisted total cross section of the studied processes depends on the produced neutral Higgs masses, the centre of mass energy and the laser field parameters. In addition, the maximum cross section occurs at high centre of mass energy for the process ${e}^{+}{e}^{-}\rightarrow H^{0}A^{0}$ as compared to that of ${e}^{+}{e}^{-}\rightarrow h^{0}A^{0}$.

hep-ph↗

arXiv2021

New Discovery Modes for a Light Charged Higgs Boson at the LHC

At the Large Hadron Collider (LHC), both the ATLAS and CMS Collaborations have been searching for light charged Higgs bosons via top (anti)quark production and decays channels, like $pp\to t \bar{t}$ with one top (anti)quark decaying into a charged Higgs boson and a $b$ (anti)quark, when the decay is kinematically open (i.e., when $m_{H^\pm}\lesssim m_t$). In this paper, we propose new searches at the LHC involving light charged Higgs bosons via their pair production channels like $pp\to H^\pm h/A$ and $pp\to H^+ H^-$ in the 2-Higgs Doublet Model (2HDM) Type-I and -X scenarios. By focusing on the case where the heavy $H$ state plays the role of the Standard Model (SM)-like Higgs boson with a mass near 125 GeV, we study the aforementioned Higgs boson pair production channels and investigate their bosonic decays, such as $H^\pm \to W^{\pm } h$ and/or $H^\pm \to W^{\pm } A$. We demonstrate that for a light charged Higgs boson state, with $m_{H^\pm}\lesssim m_t$, at the LHC, such di-Higgs production and decay channels can give rise to signatures with event rates much larger than those emerging from $pp\to t\bar{t}\to t\bar{b} H^-$ + c.c.. We specifically study $h/A\to b\bar b$ and $τ^+τ^-$ decays. We, therefore, claim that the discussed combination of new production and decay modes can result in an alternative discovery channel for charged Higgs bosons lighter than the top (anti)quark at the LHC within the above two 2HDM Types. Finally, in order to motivate experimentalists in ATLAS and CMS to search for such signatures, we propose 16 Benchmark Points (BPs) which are compatible with both theoretical and experimental constraints.

hep-ph↗

arXiv2021

Elastic scattering of a muon neutrino by an electron in the presence of a circularly polarized laser field

In view of the great contribution of neutrino-electron scattering to the deep understanding of electroweak interactions, we focus in this paper on the study of elastic scattering of a muon neutrino by an electron $(e^{-}ν_μ\rightarrow e^{-}ν_μ)$ in the presence of a circularly polarized electromagnetic field. We perform our theoretical calculation within the framework of Fermi theory using the exact wave functions of charged particles in an electromagnetic field. The expression of the differential cross section (DCS) for this process is obtained analytically in the absence and presence of the laser field. The effect of the field strength and frequency on the exchange of photons as well as on the DCS is presented and analyzed. Massive neutrino effects are also included and discussed. This study, added to the previous ones, will significantly enrich our knowledge in fundamental physics.

hep-ph↗

arXiv2021

Searching for $H^\pm\to W^{\pm} + 4γ$ signals in the 2HDM Type-I at the LHC

We analyze a new signature of a charged Higgs boson in the Type-I realization of the 2-Higgs Doublet Model (2HDM), where the mass of the charged Higgs boson satisfies the condition $M_{H^{\pm}}<M_{t}+M_{b}$ and the theoretical parameter space is consistent with the latest experimental constraints from Large Hadron Collider (LHC) and other direct as well as indirect searches. In the surviving regions, it is found that the bosonic decay mode of a charged Higgs boson is dominated by $H^{\pm} \rightarrow W^{\pm*}h$. At the same time, the light neutral Higgs boson $h$ dominantly decays into two photons. We thus find that the production process $pp \rightarrow H^{\pm}h \rightarrow W^{\pm*}h h \rightarrow l^{\pm}ν+4γ$ is almost background free. Since the $W^{\pm}$ could be either off-shell or on-shell, furthering a previous phenomenological analysis, we examine closely detector effects onto the above signature and demonstrate that it is indeed promising to study it at the LHC with both $\sqrt{s}= 13$ TeV and $\sqrt{s} = 14$ TeV, assuming an integrated luminosity of 300 $fb^{-1}$.

hep-ph↗

arXiv2021

Muon pair production via $e^{+}e^{-}$ annihilation in the presence of a circularly polarized laser field

In this paper, we have investigated the elementary particle reaction ${e}^{+} {e}^{-} \rightarrowμ^{+} μ^{-}$ that results from the electron-positron interaction, at the leading order, with an intense laser wave of circular polarization. We have derived, by annalytical means, the laser-assisted differential cross section expression by using the scattering matrix approach. We have analyzed the energy and the number of exchanged photons dependence of muon pair production in electron-positron annihilation at different centre of mass energies including the $Z$-boson peak. For this reason, a wide range of high centre of mass energies relevant to future $e^{+}e^{-}$ collider were covered to study the cross section behavior. We have found that, for a given number of exchanged photons, laser field strength and frequency, the circularly polarized laser field decreases the total cross section by several orders of magnitudes.

hep-ph↗

arXiv2021

Relativistic elastic scattering of an electron by a muon in the field of a circularly polarized electromagnetic wave

Within the framework of quantum electrodynamics, the scattering of an electron by a muon in the presence of a circularly polarized monochromatic laser field is investigated theoretically in the first Born approximation. The expressions for the amplitude and the differential cross section are derived analytically by adopting the Furry picture approach in which the calculations are carried out using exact relativistic Dirac-Volkov functions. We begin by studying the process taking into account the relativistic dressing of only the electron without muon. Then, in order to reveal the effect of the muon dressing, we fully consider the relativistic dressing of the electron and muon together in the initial and final states. As a result, the differential cross section is significantly reduced by the laser field. We find that the effect of laser-dressing of muon becomes noticeable at laser field strengths greater than or equal to $10^{9}~\text{V cm}^{-1}$ and therefore must be taken into account. The influence of the laser field strength and frequency on the differential cross section and multiphoton process is revealed. An insightful comparison with the laser-free results is also included.17

quant-ph↗

arXiv2021

Laser-assisted charged Higgs pair production in Inert Higgs Doublet Model (IHDM)

The production of a pair of charged Higgs bosons from $e^{+}e^{-}$ annihilation in the presence of a circularly polarized laser field is investigated in Inert Higgs doublet Model (IHDM) at ${e}^{+}{e}^{-}$ colliders. We have derived the analytical expression for the laser-assisted differential cross section by using the Dirac-Volkov formalism at leading order including the $Z$ and $γ$ diagrams. Since the laser-free cross section of this process depends, in the lowest order, only on the mass of the charged Higgs boson and the energy of the center of mass, we have analyzed the dependence of the total laser-assisted cross section on these parameters and also on the laser parameters such as the number of photons exchanged, the laser field intensity and its frequency. The results found indicate that the electromagnetic field decreases the order of magnitude of the total cross section as much as the laser field intensity increases or by decreasing its frequency. Moreover, it becomes high for low charged Higgs masses and low center of mass energies.

hep-ph↗

arXiv2021

Analysis of $W^\pm+4γ$ in the 2HDM Type-I at the LHC

We analyse a light charged Higgs boson in the 2-Higgs Doublet Model (2HDM) Type-I, when its mass satisfies the condition $M_{H^{\pm}} < M_{t}+M_{b}$ and the parameter space is consistent with theoretical requirements of self-consistency as well as the latest experimental constraints from Large Hadron Collider (LHC) and other data. Over such a parameter space, wherein the Standard Model (SM)-like state discovered at the LHC in 2012 is the heaviest CP-even state of the 2HDM, it is found that the decay modes of the charged Higgs boson are dominated by $H^{\pm} \rightarrow W^{\pm *} h$. Furthermore, the light neutral Higgs boson $h$ dominantly decays into two photons. Under these conditions, we find that the production and decay process $ p p \to H^\pm h \to {W^\pm}^{(*)} h h \to l ν_{l} + 4 γ$ ($l=e,μ$) is essentially background free. However, since the $W^{\pm(*)}$ could be largely off-shell and the $h$ state is very light, so that both the lepton coming from the former and the photons coming from the latter could be rather soft, we perform here a full Monte Carlo (MC) analysis at the detector level demonstrating that such a $W^{\pm} + 4γ$ signal is very promising, as it would be yielding significant excesses at the LHC with an integrated luminosity of $L=$ 300 $fb^{-1}$ at both $\sqrt{s}= 13$ and $14 ~\text{TeV}$.

hep-ph↗

arXiv2021

Signature of 2HDM at Higgs Factories

The full one-loop corrections, both the weak and QED corrections, to the process $e^+ e^- \to Z ϕ$ ($ϕ=h^0,H^0$) in the two Higgs doublet model (2HDM) at the Higgs factories are presented. Up to the $O(α_{em})$ level, the virtual corrections are evaluated by using the FeynArts/FormCalc packages. The real emission corrections are computed using the Feynman Diagram Calculation (FDC) package and the collinear divergences are regularized by the structure functions of an electron. Using the FeynArts/FormCalc and the FDC packages, we study the corrections in the Standard Model (SM) and the 2HDM, respectively. Gauge dependence arising in the normalization of mixing angles is removed by using the pinch technique. After taking into account experimental constraints from the current LHC data, we propose four interesting benchmark scenarios for future colliders. By using these benchmark scenarios, we evaluate the deviation of $Δσ(e^+ e^- \to Z ϕ)$ from their SM values. We also examine Higgs boson decays $ϕ\to b\bar{b}$ and $ϕ\to τ^+τ^-$, which can have large electroweak (EW) contributions from triple Higgs couplings which are absent in the SM. It is found that for these benchmark scenarios, both EW and real emission corrections are sizeable and could be measured at a future $e^+ e^-$ colliders such as the ILC, CLIC, and CEPC.

hep-ph↗

arXiv2019

Associated production of SM Higgs with a photon in type-II seesaw models at the ILC

We consider the production of a single Standard Model (SM) Higgs boson ($h^0$) in association with a photon at the future Linear collider (LC) in the context of a type-II seesaw model. The type-II seesaw model extends the SM particle content by adding one triple Higgs where its Higgs coupling is a key parameter of the scalar potential triggering the electroweak symmetry-breaking mechanism in the SM. It is a well motivated model since it provides neutrino masses and mixing. The LC presents a particularly interesting possibility to probe Higgs couplings due to the clean beams in the initial state. We study the one loop processes $e^+e^- \to h^0γ$ and $e^-γ\to e^- h^0$, we show that it is possible to correlate the total cross section predictions with the couplings $h^0γγ$ and $h^0γZ$ which are sensitive to the presence of singly and doubly charged Higgs. For parameter points allowed by the current experimental constraints, our numerical results show that the effect of $H^\pm$ and $H^{\pm\pm}$ can be as large as $\pm$ 25\% with respect to the SM predictions. For both processes, we also present differential cross section for different center of mass energy.

hep-ph↗

arXiv2018

Extended Higgs sector of 2HDM with real singlet facing LHC data

We study the phenomenology of the two Higgs doublet model with a real singlet scalar $S$ (2HDMS). The model predicts three CP-even Higgses $h_{1,2,3}$, one CP-odd $A^0$ and a pair of charged Higgs. We discuss the consistency of the 2HDMS with theoretical as well as with all available experimental data. In contrast with previous studies, we focus on the scenario where $h_2$ is the Standard Model (SM) 125 GeV Higgs, while $h_1$ is lighter than $h_2$ which may open a window for Higgs to Higgs decays. We perform an extensive scan into the parameter space of 2HDMS of type I and explore the effect of the singlet-doublet admixture. We found that a large singlet-doublet admixture is still compatible with the recent Higgs data from LHC. Moreover, we show that $h_1$ could be quasi-fermiophobic and would decay dominantly into two photons. We also study in details the consistency of the non-detected decay of $h_2\to h_1 h_1$ with LHC data followed by $h_1\to γγ$ which leads to four photons final state at LHC: $pp\to h_2\to h_1 h_1\to 4γ$. Using the results of null searches of multi-photons carried by the ATLAS collaboration, we have found that a large area of the parameter space is still allowed. We also demonstrate that various neutral Higgs of the 2HDMS could have several exotic decays.

hep-ph↗

arXiv2018

Phenomenology of 2HDM with VLQs

In this paper, we examine the consistency of the Large Hadron Collider (LHC) data collected during Run 1 and 2 by the ATLAS and CMS experiments with the predictions of a 2-Higgs Doublet Model (2HDM) embedding Vector-Like Quarks (VLQs) for $pp \to H,A$ production and $H,A\toγγ$ decay mechanisms, respectively, of (nearly) degenerate CP-even ($H$) and CP-odd ($A$) Higgs bosons. We show that a scenario containing one single VLQ with Electro-Magnetic (EM) charge $2/3$ can explain the above ATLAS and CMS data for masses in the region 350 GeV $\leq m_{\rm VLQ}\leq 1.5$ TeV or so, depending on $\tanβ$, and for several values of the mixing angle between the top quark ($t$) and its VLQ counterpart ($T$).We then perform a global fit onto the model by including all relevant experimental as well as theoretical constraints. The surviving samples of our analysis are discussed within 2$σ$ of the LHC measurements. Additionally, we also comment on the recent anomalous result reported by CMS using Run 2 data on the associated Standard Model (SM) Higgs boson production with top quark pairs $pp\to t\bar th$ with an observed significance of 3.3$σ$. Other than these specific examples, we also present a phenomenological analysis of the main features of the model, including the most promising $T$ decay channels.

hep-ph↗

arXiv2017

$R_{K^{(*)}}$ anomaly in type-III 2HDM

Recent experimental results provided by the CMS and LHCb, Belle and BaBar collaborations are showing a tension with the SM predictions in $R_{K^{(*)}}$, which might call for an explanation from new physics. In this work, we examine this tension in the type-III two-Higgs doublet models. We focus on the contributions of charged Higgs boson to the observable(s) $R_{K^{(*)}}$ and other rare processes $ΔM_q$ ($q=s,d$), $B \to X_s γ$ $B_s \to μ^+ μ^{-}$ and $B_q \to X_s μ^+ μ^{-}$, which are governed by the same effective Hamiltonian. It is found that regions of large $\tanβ$ and light charged Higgs mass $m_{H^\pm}$ can explain the measured value of $R_{K^{(*)}}$ and accommodate other B physics data as well. In contrast, the type-II two-Higgs doublet model can not.

hep-ph↗

arXiv2017

Influence of C$_{6}$H$_{4}$(OH)$_{2}$ isomers on water disinfection by photocatalysis: a computational study

Solar disinfection by photocatalysis is one of the promising methods used for drinking water disinfection. It leads to the destruction of bacteria like $Escherichia$ $Coli$ ($E.$ $Coli$). In this paper, we compare our theoretical results with experimental ones done previously by A.G. Rincón and his colleagues concerning the order of decay of C$_{6}$H$_{4}$(OH)$_{2}$ isomers in the presence of titanium dioxide TiO$_{2}$, and show the influence of optical properties of those molecules on $E.$ $Coli$ inactivation. According to the adsorption energy parameter, we find that catechol has the highest adsorption degree on titanium dioxide, followed by resorcinol, and finally hydroquinone. Three dihydroxybenzene isomers absorb photons belonging to ultraviolet (UV) range. The lowest absorption energies of resorcinol, catechol and hydroquinone are respectively 3.42, 4.44 and 4.49 eV.

cond-mat.soft↗

arXiv2017

Triple Higgs coupling effect on $h^0 \to b \bar b$ and $h^0 \to τ^+ τ^-$ in the 2HDM

We study the one loop electroweak radiative corrections to $h^0\to b\bar{b}$ and $h^0\to τ^+τ^-$ in the framework of two Higgs doublet Model (2HDM). We evaluate the deviation of these couplings from their Standard Model (SM) values. $h^0\to b\bar{b}$ and $h^0\to τ^+τ^-$ may receives large contribution from triple couplings $h^0H^0H^0$, $H^0h^0h^0$, $h^0A^0A^0$ and $h^0H^+H^-$ which are absent in the Standard Model. It is found that in 2HDM, these corrections could be significant and may reach more than 20\% for not tow heavy $H^0$ or $A^0$ or $H^\pm$. We also study the ratio of branching ratios $R=BR(h^0\to b\bar{b})/BR(h^0\to τ^+τ^-)$ of Higgs boson decays which could be used to disentangle SM from other models such as 2HDM.

hep-ph↗

arXiv2016

$h,Z\to \ell_i \bar\ell_j$, $Δa_μ$, $τ\to (3μ,μγ)$ in generic two-Higgs-doublet models

Inspired by a significance of $2.4σ$ in $h\to μτ$ decay observed by CMS at $\sqrt{s} = 8$ TeV, we investigate the Higgs lepton flavor violating effects in the generic two-Higgs-doublet model (GTHDM), where the lepton flavor changing neutral currents are induced at tree level and arisen from Yukawa sector. We revisit the constraints for GTHDM by considering theoretical requirements, precision measurements of $δρ$ and oblique parameters $S$, $T$, $U$ and Higgs measurements. The bounds from Higgs data now play the major role. With the values of parameters that simultaneously satisfy the Higgs bounds and the excess of Higgs coupling to $μ$-$τ$ at CMS, we find that the tree-level $τ\to 3μ$ and loop-induced $τ\to μγ$ could be consistent with current experimental upper limits; the discrepancy in muon $g-2$ between experiment and standard model prediction could be solved; and an interesting relation between muon $g-2$ and branching ratio (BR) for $μ\to e γ$ is found. The GTHM results that the ratio $BR(h\to eτ)/BR(h\to μτ)$ should be smaller than $10^{-4}$ in order of magnitude. Additionally, we also study the rare decay $Z\to μτ$ and get $BR(Z\to μτ)< 10^{-6}$.

hep-ph↗

arXiv2016

Higgs singlet boson as a diphoton resonance in a vector-like quark model

ATLAS and CMS recently show the first results from run 2 of the Large Hadron Collider (LHC) at $\sqrt{s}=13$ TeV. A resonant bump at a mass of around 750 GeV in the diphoton invariant mass spectrum is indicated and the corresponding diphoton production cross section is around 3-10 fb. Motivated by the LHC diphoton excess, we propose that the possible resonance candidate is a Higgs singlet. To produce the Higgs singlet via gluon-gluon fusion process, we embed the Higgs singlet in the framework of vector-like triplet quark (VLTQ) model. As a result, the Higgs singlet decaying to diphoton final state is via VLTQ loops. Using the enhanced number of new quarks and new Yukawa couplings of the VLTQs and Higgs singlet, we successfully explain the diphoton production cross section. We find that the width of the Higgs singlet is below 1 GeV, its production cross section can be of order of 1 pb at $\sqrt{s}=13$ TeV, and the branching ratio for it decaying to diphoton is around $0.017$ and is insensitive to the masses of VLTQs and new Yukawa couplings. We find a strong correlation between the Higgs Yukawa couplings to $s$-$b$ and $c$-$t$; the resulted branching ratio for $t \to c h$ can be $1.1\times 10^{-4}$ when the constraint from $B_s$ oscillation is applied. With the constrained parameter values, the signal strength for the SM Higgs decaying to diphoton is $μ_{γγ}< 1.18$, which is consistent with the current measurements at ATLAS and CMS.

hep-ph↗

arXiv2016

Two-Higgs-Doublet type-II and -III models and $t\to c h$ at the LHC

We study the constraints of the generic two-Higgs-doublet model (2HDM) type-III and the impacts of the new Yukawa couplings. For comparisons, we revisit the analysis in the 2HDM type-II. To understand the influence of all involving free parameters and to realize their correlations, we employ $χ$-square fitting approach by including theoretical and experimental constraints, such as S, T, and U oblique parameters, the production of standard model Higgs and its decay to $γγ$, $WW^*/ZZ^*$, $τ^+τ^-$, etc. The errors of analysis are taken at $68\%$, $95.5\%$, and $99.7\%$ confidence levels. Due to the new Yukawa couplings being associated with $\cos(β-α)$ and $\sin(β-α)$, we find that the allowed regions for $\sinα$ and $\tanβ$ in the type-III model can be broader when the dictated parameter $χ_F$ is positive; however, for negative $χ_F$, the limits are stricter than those in the type-II model. By using the constrained parameters, we find that the deviation from the SM in the $h\to Zγ$ can be of ${\cal O}(10\%)$. Additionally, we also study the top-quark flavor-changing processes induced at the tree level in the type-III model and find that when all current experimental data are considered, we get $Br(t\to c(h, H) )< 10^{-3}$ for $m_h=125.36$ and $m_H=150$ GeV and $Br(t\to cA)$ slightly exceeds $10^{-3}$ for $m_A =130$ GeV.

hep-ph↗