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Mbark Berrouj

Publications and source records attributed to Mbark Berrouj.

4 recordsLinked to original sources

Probing Heavy Neutral Higgs Bosons via Single Vector-Like Bottom Quark Production at the HL-LHC

We investigate the discovery prospects of a singly produced vector-like bottom quark in the Type-II Two-Higgs-Doublet Model extended by an $SU(2)_L$ vector-like $(T,B)$ doublet. We focus on the non-standard decay chain $B \to ϕb$, followed by $ϕ\to t\bar{t}$, where $ϕ= H$ or $A$, leading to a final state with one charged lepton, missing transverse energy, and multiple $b$-jets. We perform a full simulation of both signal and Standard Model backgrounds at $\sqrt{s}=14$ TeV. We show that the exotic channels $B \to ϕb$ can dominate over the conventional decay modes, reaching branching ratios of order $50\%$ for both neutral scalars in the alignment limit. A conventional cut-based analysis provides a $5σ$ discovery significance only at sufficiently high integrated luminosity. By contrast, an XGBoost-based multivariate analysis substantially improves the signal-background discrimination and extends the discovery reach up to $m_B \simeq 1.3$ TeV with $600~\mathrm{fb}^{-1}$ and up to $m_B \simeq 1.6$ TeV with $3~\mathrm{ab}^{-1}$, even in the presence of systematic uncertainties as large as $15\%$.

hep-ph

Impact of hidden heavy Higgs channels of VLB-Quarks below 1 TeV in 2HDM

We investigate the phenomenological impact of incorporating vector-like bottom (VLB) quarks into the Type-II Two-Higgs-Doublet Model (2HDM-II). This framework introduces novel beyond-Standard-Model (BSM) decay channels $B \to Hb$, $B \to Ab$, and $B \to H^-t$, which are typically ignored by LHC pair-production searches focused on Standard Model (SM) final states ($B \to Zb$, $B \to hb$, $B \to Wt$). Our analysis reveals that these BSM pathways significantly weaken current VLB mass constraints. In the 2HDM-II alignment limit, the mass limit for a singlet $B$ shifts from approximately 1.5 TeV down to 1.34 TeV. For $(T, B)$ and $(B, Y)$ doublet configurations, the mass limits relax further to approximately 0.98 TeV, driven by the dominance of $B \to Hb$ and $B \to Ab$ decays, which can reach combined branching ratios of nearly 100\%.

hep-ph

Search for charged Higgs bosons through vector-like top quark pair production at the LHC

We investigate the discovery prospects for a vector-like top partner (VLT) in the Type-II Two-Higgs-Doublet Model (2HDM-II) extended by a vector-like quark doublet ($TB$) at the 14~TeV LHC. The study focuses on the pair production process $pp \to T\bar{T} \to bH^+\, \bar{b}H^- \to b(tb)\, \bar{b}(\bar{t}b)$, yielding fully hadronic final states characterized by high $b$-jet multiplicity. Two analysis strategies are employed, requiring at least four or five $b$-tagged jets (4$b$ and 5$b$), to exploit the signal topology. Assuming a charged Higgs mass of $m_{H^\pm} \sim 600$~GeV and a systematic uncertainty of $δ= 5\%$, the 4$b$ channel enables discovery up to $m_T \sim 1200$~GeV at $\mathcal{L} = 300~\text{fb}^{-1}$, while the 5$b$ analysis extends the reach to $m_T \sim 1300$~GeV. At higher luminosities of 1000--3000~fb$^{-1}$, the 5$b$ strategy achieves discovery sensitivity up to $m_T \sim 1400$~GeV. The reach is significantly reduced as $m_{H^\pm}$ increases, due to the suppression of the $\text{BR}(T \to H^+ b)$: for $m_{H^\pm} \sim 1000$~GeV, discovery becomes unattainable across all luminosity and systematic uncertainty configurations. Sensitivity is also strongly impacted by systematic uncertainties: for $δ= 10\%$ and $m_{H^\pm} < 1000$~GeV, discovery remains viable up to $m_T \sim 1200$~GeV in the 5$b$ analysis, while for $δ= 20\%$, no discovery is achievable for $m_T \geq 1000$~GeV.

hep-ph

Investigation of Charged Higgs Bosons Production from Vector-Like $T$ Quark Decays at $eγ$ Collider

Within the extended framework of the Two-Higgs-Doublet Model Type II (2HDM-II), enhanced by a vector-like quark (VLQ) doublet $TB$, we present a comprehensive analysis of the process $e^{-}γ\rightarrow bν_{e}\bar{T}$ at future high-energy $eγ$ colliders, focusing on the decays $\bar{T} \rightarrow H^{-} \bar{b}$ and $H^{-} \rightarrow \bar{t}b$. Using current theoretical and experimental constraints, we calculate production cross sections for both unpolarized and polarized beams at center-of-mass energies of $\sqrt{s} = 2$ and 3 TeV, demonstrating that polarized beams significantly enhance detection prospects by increasing production rates. By analyzing kinematic distributions, we establish optimized selection criteria to effectively separate signal events from background. At $\sqrt{s} = 2$ TeV with an integrated luminosity of 1500 fb$^{-1}$, we find exclusion regions within $s_R^d\in[0.085,0.16]$ for $m_T\in [1000,1260]$ GeV and a discovery potential within $s_R^d\in[0.14,0.17]$ for $m_T\in[1000,1100]$ GeV, with these regions expanding to $s_R^d\in [0.05,0.15]$ for $m_T\in[1000,1340]$ GeV and $s_R^d \in [0.11, 0.17]$ for $m_T\in[1000,1160]$ GeV at 3000 fb$^{-1}$. At $\sqrt{s} = 3$ TeV and 1500 fb$^{-1}$, we identify exclusion regions of $s_R^d\in[0.055,0.135]$ for $m_T \in [1000, 1640]$ GeV and discovery regions of $s_R^d \in [0.09, 0.15]$ for $m_T \in [1000, 1400]$ GeV, which further expand to $s_R^d \in [0.028, 0.12]$ for $m_T\in[1000,1970]$ GeV and $s_R^d \in[0.04,0.122]$ for $m_T\in[1000,1760]$ GeV at 3000 fb$^{-1}$. Our findings emphasize the increased detection potential at higher center-of-mass energies, particularly at 3 TeV compared to 2 TeV, with notable improvements when polarized beams are utilized. We also account for the effects of initial state radiation, beamstrahlung, and systematic uncertainties, which influence both exclusion and discovery prospects.

hep-ph