arXiv subjects

Abdesslam Arhrib

Publications and source records attributed to Abdesslam Arhrib.

At least 55 records · Page 3Linked to original sources

arXiv2017

Multi-photon production in the Type-I 2HDM

This paper presents a study of a possible contribution to a Higgs boson signal in the $hh\to γγγγ$ channel due to $H\to hh$ decays, in the framework of the CP-conserving 2-Higgs Doublet Model Type-I (2HDM-I), where the heavier of the two CP-even Higgs bosons defined herein, $H$, is the SM-like Higgs state observed with a mass of 125 GeV at the Large Hadron Collider (LHC). We perform a broad scan of the 2HDM-I parameter space, in presence of both up-to-date theoretical and experimental constraints, in order to extract the interesting regions yielding such a signal. Then, after validating our numerical framework against public experimental analyses carried out at the LHC, we proceed to assess its scope in constraining and/or extracting the $gg\to H\to hh\to γγγγ$ signal in presence of a sophisticated Monte Carlo (MC) simulation. We find that, over a substantial region of the 2HDM-I parameter space presently un-accessible, the LHC will be able to establish such a potential signature in the next 2--3 years.

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arXiv2017

Signal to background interference in $pp\to t H^-\to t W^- b\bar b$ at the LHC Run-II

We investigate in the Large Hadron Collider (LHC) environment the possibility that sizeable interference effects between a {\sl heavy} charged Higgs boson signal produced via $bg\to tH^-$ (+ c.c.) scattering and decaying via $H^-\to W^- A\to W^- b\bar b$ (+ c.c.) and the irreducible background given by $bg\to t W^- b\bar b$ topologies could spoil current search approaches where the former and latter channels are treated separately. The rationale for this comes from the fact that a heavy charged Higgs state can have a large width, and so can happen for the CP-odd neutral Higgs state emerging in the ensuing decays well, which in turn enables such interferences. We conclude that effects are very significant, both at the inclusive and exclusive level (i.e., both before and after $H^\pm$ selection cuts are enforced, respectively) and typically of a destructive nature. This therefore implies that currently established LHC reaches for heavy charged Higgs bosons require some level of rescaling. However, this is possible a posteriori, as the aforementioned $H^\pm$ selection cuts shape the interference contributions at the differential level in a way similar to that of the isolated $H^\pm$ signal, so there is no need to reassess the efficiency of the individual cuts. We show such effects quantitatively by borrowing benchmarks points from different Yukawa types of a 2-Higgs Doublet Model parameter space for $H^\pm$ values starting from around 200 GeV.

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arXiv2017

Identifying a light charged Higgs boson at the LHC Run II

We analyse the phenomenological implications of a light Higgs boson, $h$, within the CP-conserving 2-Higgs Doublet Model (2HDM) Type-I, for the detection prospects of the charged $H^\pm$ state at Run II of the Large Hadron Collider (LHC), assuming $\sqrt{s}=13$ TeV as energy and ${\cal O}(100~{\rm fb}^{-1})$ as luminosity. When sufficiently light, this $h$ state can open up the bosonic decay channel $H^\pm \to W^{\pm(*)}h$, which may have a branching ratio significantly exceeding those of the $H^\pm \to τν$ and $H^\pm \to cs$ channels. We perform a broad scan of the 2HDM Type-I parameter space, assuming the heavier of the two CP-even Higgs bosons, $H$, to be the observed SM-like state with a mass near 125 GeV. Through these scans we highlight regions in which $m_{H^\pm} < m_t +m_b$ that are still consistent with the most recent limits from experimental searches. We find in these regions that, when the $H^\pm \to W^{\pm(*)}h$ decay mode is the dominant one, the $h$ can be highly fermiophobic, with a considerably large decay rate in the $γγ$ channel. This can result in the total cross section of the $σ(pp\to H^\pm h \to W^{\pm(*)} + 4γ)$ process reaching up to ${\cal O}(100~{\rm fb})$. We therefore investigate the possibility of observing this spectacular signal at the LHC Run II.

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arXiv2017

Bosonic Decays of Charged Higgs Bosons in a 2HDM Type-I

In this study, we focus on the bosonic decays of light charged Higgs bosons in the 2-Higgs Doublet Model (2HDM) Type-I. We quantify the Branching Ratios (BRs) of the $H^\pm \to W^\pm h$ and $H^\pm\to W^\pm A$ channels and show that they could be substantial over several areas of the parameter space of the 2HDM Type-I that are still allowed by Large Hadron Collider (LHC) and other experimental data as well as theoretical constraints. We suggest that $H^\pm \to W^\pm h$ and/or $H^\pm \to W^\pm A$ could be used as a feasible discovery channel alternative to $H^\pm \to τν$.

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arXiv2016

Radiative Model of Neutrino Mass with Neutrino Interacting MeV Dark Matter

We consider the radiative generation of neutrino mass through the interactions of neutrinos with MeV dark matter. We construct a realistic renormalizable model with one scalar doublet and one complex singlet together with three light singlet Majorana fermions, all transforming under a dark U(1) symmetry which breaks softly to Z_2. We study in detail the scalar sector which supports this specific scenario and its rich phenomenology.

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arXiv2016

Enhanced Charged Higgs Production through W-Higgs Fusion in W-b Scattering

We study the associated production of a charged Higgs boson with a bottom quark and a light quark at the LHC via p p \to H^\pm\,b\,j in the Two Higgs Doublet Models (2HDMs). Using the effective W approximation, we show that there is exact cancellation among various Feynman diagrams in high energy limit. This may imply that the production of charged Higgs can be significantly enhanced in the presence of large mass differences among the neutral Higgs bosons via W^\pm-Higgs fusion in the p p \to H^\pm\,b\,j process. Particularly, we emphasize the potential enhancement due to a light pseudoscalar boson $A$, which is still allowed by the current data by which we explicitly calculate the allowed regions in (M_A,\,\tanβ) plane, and show that the production cross section can be as large as 0.1 pb for large $\tanβ$. We also show that the transverse momentum distribution of the b quark can potentially distinguish the W^\pm-A fusion diagram from the top diagram. Finally, we point out further enhancement when we go beyond the 2HDMs.

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arXiv2015

Radiative corrections to the Triple Higgs Coupling in the Inert Higgs Doublet Model

We investigate the implication of the recent discovery of a Higgs-like particle in the first phase of the LHC Run 1 on the Inert Higgs Doublet Model (IHDM). The determination of the Higgs couplings to SM particles and its intrinsic properties will get improved during the new LHC Run 2 starting this year. The new LHC Run 2 would also shade some light on the triple Higgs coupling. Such measurement is very important in order to establish the details of the electroweak symmetry breaking mechanism. Given the importance of the Higgs couplings both at the LHC and $e^+e^-$ Linear Collider machines, accurate theoretical predictions are required. We study the radiative corrections to the triple Higgs coupling $hhh$ and to $hZZ$, $hWW$ couplings in the context of the IHDM. By combining several theoretical and experimental constraints on parameter space, we show that extra particles might modify the triple Higgs coupling near threshold regions. Finally, we discuss the effect of these corrections on the double Higgs production signal at the $e^+e^-$ LC and show that they can be rather important.

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arXiv2015

Triple Higgs Coupling as a Probe of the Twin-Peak Scenario

In this letter, we investigate the case of a twin peak around the observed 125 GeV scalar resonance, using di-Higgs production processes at both LHC and $e^{+}e^{-}$ Linear Colliders. We have shown that both at LHC and Linear Collider the triple Higgs couplings play an important role to identify this scenario; and also that this scenario can be distinguishable from any Standard Model extension by extra massive particles which might modify the triple Higgs coupling. We also introduce a criterion that can be used to ruled out the twin peak scenario.

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arXiv2014

Type II Seesaw Higgsology and LEP/LHC constraints

In the {\sl type II seesaw} model, if spontaneous violation of the lepton number conservation prevails over that of explicit violation, a rich Higgs sector phenomenology is expected to arise with light scalar states having mixed charged-fermiophobic/neutrinophilic properties. We study the constraints on these light CP-even ($h^0$) and CP-odd ($A^0$) states from LEP exclusion limits, combined with the so far established limits and properties of the $125-126$~GeV ${\cal H}$ boson discovered at the LHC. We show that, apart from a fine-tuned region of the parameter space, masses in the $\sim 44$ to $80$ GeV range escape from the LEP limits if the vacuum expectation value of the Higgs triplet is $\lesssim {\cal O}(10^{-3})$GeV, that is comfortably in the region for 'natural' generation of Majorana neutrino masses within this model. In the lower part of the scalar mass spectrum the decay channels ${\cal H} \to h^0 h^0, A^0 A^0$ lead predominantly to heavy flavor plus missing energy or to totally invisible Higgs decays, mimicking dark matter signatures without a dark matter candidate. Exclusion limits at the percent level of these (semi-)invisible decay channels would be needed, together with stringent bounds on the (doubly-)charged states, to constrain significantly this scenario. We also revisit complementary constraints from ${\cal H} \to γγ$ and ${\cal H} \to Z γ$ channels on the (doubly)charged scalar sector of the model, pinpointing non-sensitivity regions, and carry out a likeliness study for the theoretically allowed couplings in the scalar potential.

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arXiv2014

An Updated Analysis of Inert Higgs Doublet Model in light of the Recent Results from LUX, PLANCK, AMS-02 and LHC

In light of the recent discovery by the ATLAS and CMS experiments at the Large Hadron Collider (LHC) of a Higgs-like particle with a narrow mass range of 125-126 GeV, we perform an updated analysis on one of the popular scalar dark matter models, the Inert Higgs Doublet Model (IHDM). We take into account in our likelihood analysis of various experimental constraints, including recent relic density measurement, dark matter direct and indirect detection constraints as well as the latest collider constraints on the invisible decay width of the Higgs boson and monojet search at the LHC. It is shown that if the invisible decay of the standard model Higgs boson is open, LHC as well as direct detection experiments like LUX and XENON100 could put stringent limits on the Higgs boson couplings to dark matter. We find that the most favoured parameter space for IHDM corresponds to dark matter with a mass less than 100 GeV or so. In particular, the best-fit points are at the dark matter mass around 70 GeV where the invisible Higgs decay to dark matter is closed. Scalar dark matter in the higher mass range of 0.5-4 TeV is also explored in our study. Projected sensitivities for the future experiments of monojet at LHC-14, XENON1T and AMS-02 one year antiproton flux are shown to put further constraints on the existing parameter space of IHDM.

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arXiv2014

Associated Production of Higgs at Linear Collider in the Inert Higgs Doublet Model

We study the correlation between the Standard Model Higgs decay $h\to γγ$ and $h\to Z γ$ in the Inert Higgs Doublet Model. It is found that these two one-loop-induced decays are positively correlated, with the later channel having slightly smaller branching ratio than the former one. At the Linear Collider, we study the interplay of the off-shell extension of these two amplitudes that contributed significantly to the associated production of the Higgs boson with a photon in the process $e^+ e^- \to γh$ and with an electron in the process $e^-γ\to e^- h$ in the $s$ and $t$ channels respectively via both $γ$ and $Z$ exchange for each process.

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arXiv2014

Higgs Phenomenology in the Two-Singlet Model

We study the phenomenology of the Standard Model (SM) Higgs sector extended by two singlet scalars. The model predicts two CP-even scalars $h_{1,2}$ which are a mixture of doublet and singlet components as well as a pure singlet scalar $S_{0}$ which is a dark matter candidate. We show that the model can satisfy the relic density and direct detection constraints as well as all the recent ATLAS and CMS measurements. We also discuss the effect of the extra Higgs bosons on the different Higgs triple couplings $h_{i}h_{j}h_{k}$, $i,j,k=1,2$. A particular attention is given to the triple self-coupling of the SM-like Higgs where we found that the one loop corrections can reach $150\%$ is some cases. We also discuss some production mechanisms for $h_{1}$ and $h_{2}$ at the LHC as well as at the future International Linear Collider. It is found that the production cross section of a pair of SM-like Higgs bosons could be much larger than the corresponding one in the SM and would reveal physics beyond the SM if observable. We also show that in this model the branching ratio of the SM-like Higgs decaying to two singlet scalars could be of the order of $20\%$, therefore the production of the SM Higgs followed by its decay to a pair of singlets would be an important source of production of singlet scalars.

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arXiv2013

Higgs to mu tau Decay in Supersymmetry without R Parity

In this letter, we report on lepton flavor violating Higgs decay into mu+tau in the framework of the generic supersymmetric standard model without R parity and list interesting combinations of R-parity violating parameters. We impose other known experimental constraints on the parameters of the model and show our results from the R-parity violating parameters. In our analysis, the branching ratio of Higgs to mu+tau can exceed 10^{-5} within admissible parameter space.

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arXiv2013

Comprehensive Analysis on Lepton Flavor Violating Higgs Boson to mu tau Decay in Supersymmetry without R Parity

In this paper we examine thoroughly the Higgs boson to mu tau decay via processes involving R parity violating couplings. By means of full one-loop diagrammatic calculations, we found that even if known experimental constraints, particularly including the stringent sub-eV neutrino mass bounds, give strong restrictions on some of the R parity violating parameters, the branching ratio could still achieve notable value in the admissible parameter space. Hence, the flavor violating leptonic decay is of interest to future experiments. We present here key results of our analysis. Based on the analysis, we give some comments on h -> e mu and h -> e tau also.

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arXiv2012

H\toγγin the Complex Two Higgs Doublet Model

We explore the parameter regions in the complex Two Higgs Doublet Model (c2HDM) with explicit CP violation that can describe current LHC hints for one or more Higgs boson signals at 125 GeV. Such a simple extension of the Standard model has three neutral Higgs bosons and a pair charged Higgs and leads to rich CP-violating sources including the CP-even CP-odd mixing of the neutral Higgs bosons. Within this model we present the production of light Higgs boson at the LHC followed by its decay into two photons. Our numerical study takes into account theoretical and experimental constraints on the Higgs potential like positivity, unitarity and perturbativity as well as $ρ$-parameter, $b\to sγ$ and $R_b$. These requirement together with the minimum conditions could explain the di-photon excess observed at the LHC. We also discuss the effects of the CP violating phases on the CP violation observable which is the difference between left-circular and right-circular polarization.

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arXiv2012

Two Higgs Doublet Model in light of the Standard Model H -> tau^+ tau^- search at the LHC

We study the implications of the searches based on H -> tau^+ tau^- by the ATLAS and CMS collaborations on the parameter space of the two Higgs doublet model (2HDM). In the 2HDM, the scalars can decay into a tau pair with a branching ratio larger than the SM one, leading to constraints on the 2HDM parameter space. We have also discussed the implications for the 2HDM of the recent di-muon search by the ATLAS collaboration for a CP-odd scalar in the mass range 4-12 GeV.

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arXiv2012

h\to γγIn Inert Higgs Doublet Model

Motivated by the recent result reported from LHC on the di-photon search for a Standard Model (SM) Higgs-like boson. We discuss the implications of this possible signal in the framework of the Inert Higgs Doublet Model (IHDM), taking into account previous limits from Higgs searches at LEP, the Tevatron and the LHC as well as constraints from unitarity, vacuum stability and electroweak precision tests. We show that the charged Higgs contributions can interfere constructively or destructively with the W gauge bosons loops leading to enhancement or suppression of the di-photon rate with respect to SM rate. We show also that the invisible decay of the Higgs, if open, could affect the total width of the SM Higgs boson and therefore suppress the di-photon rate.

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arXiv2011

Pair production of neutralinos and charginos at the LHC: the role of Higgs bosons exchange

We analyze the effects of the s-channel Higgs bosons exchange on the charginos and neutralinos-pair production in proton-proton collision at the CERN Large Hadron Collider (LHC) in the following channels: $pp \to \Cha^+\Cha^-/\Neu^0\Neu^0 + X$, within the minimal supersymmetric standard model (MSSM). Assuming the usual GUT relation between $M_1$ and $M_2$ at the weak scale, we found that substantial enhancement can be obtained through s-channel Higgs bosons exchange in the mixed regime where $M_2 \sim |μ|$ with moderate to large $\tanβ$ at the resonance of the heavy Higgs bosons. By Combining the phenomenological constraints on neutralinos and charginos, we may still find regions of parameter space where charginos and neutralinos-pair production at the LHC from $b\bar b$ initial state can be large and observable at LHC. We also compute the full complete set of electroweak (EW) contributions to $pp\to gg\to \Cha^+\Cha^-/\Neu^0\Neu^0 + X$ at one loop level in the general MSSM. The analytical computation of the complete tree level amplitude for $b\bar{b} \to \Cha^+\Cha^-/\Neu^0\Neu^0 + X$, including s-channel Higgs exchange, is given.

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