Current status of MSSM Higgs sector with LHC 13 TeV data

ATLAS and CMS collaborations have reported the results on the Higgs search analyzing $\sim 36$ fb$^{-1}$ data from Run-II of LHC at 13 TeV. In this work, we study the Higgs sector of the phenomenological Minimal Supersymmetric Standard Model, in light of the recent Higgs data, by studying separately the impact of Run-I and Run-II data. One of the major impacts of the new data on the parameter space comes from the direct searches of neutral CP-even and CP-odd heavy Higgses ($H$ and $A$, respectively) in the $H/A \to \tau^{+} \tau^{-}$ channel which disfavours high $\tan\beta$ regions more efficiently than Run-I data. Secondly, we show that the latest result of the rare radiative decay of $B$ meson imposes a slightly stronger constraint on low $\tan \beta$ and low $M_A$ region of the parameter space, as compared to its previous measurement. Further, we find that in a global fit Run-II light Higgs signal strength data is almost comparable in strength with the corresponding Run-I data. Finally, we discuss scenarios with the Heavy Higgs boson decaying into electroweakinos and third generation squarks and sleptons.Comment: 51 pages, 22 figure

Di-Higgs resonance searches in weak boson fusion

The search for di-Higgs final states is typically limited at the LHC to the dominant gluon fusion channels, with weak boson fusion only assuming a spectator role. In this work, we demonstrate that when it comes to searches for resonant structures that arise from isosinglet mixing in the Higgs sector, the weak boson fusion sideline can indeed contribute to winning the discovery game. Extending existing experimental resonance searches by including both contributions is therefore crucial

Constraining Lepton Flavor Violating Higgs Couplings at the HL-LHC in the Vector Boson Fusion Channel

We explore the parameter space of lepton flavor violating (LFV) neutral Higgs Yukawa couplings with the muon and tau leptons that can be probed at the high-luminosity Large Hadron Collider (HL-LHC) via the vector boson fusion~(VBF) Higgs production process. Our projected sensitivities for the Standard Model Higgs ($h$) LFV branching ratio ${\rm Br}(h \to \mu\tau)$ in the $pp \to h j j \to (h \to \mu \tau) jj$ channel at the HL-LHC are contrasted with the current and future low-energy constraints from the anomalous magnetic moment and electric dipole moment of the muon, as well as with other LFV observables, such as $\tau\to 3\mu$ and $\tau\to \mu\gamma$. We also study the LFV prospects of a generic beyond the Standard Model neutral Higgs boson ($H$) with a mass in the range of $m_{H}\in [20,800]~$GeV and give the projected model-independent upper limits on the VBF production cross-section of $Hjj$ times the branching ratio of $H\to \mu\tau$ at the HL-LHC. We interpret these results in the context of a two-Higgs doublet model as a case study.Comment: 16 pages, 8 figures, 6 tables. Revised version, to appear in Phys. Rev.

Resonant heavy Higgs searches at the HL-LHC

In this work, we show the importance of searches for heavy resonant scalars (H) and pseudoscalars (A). Taking cue from the present searches, we make projections for searches in an extended scalar sector at the high luminosity run of the Large Hadron Collider. We study the three most relevant search channels, i.e., H → hh, H/A → t t¯ and bbH/A. Upon studying multifarious final states for the resonant double Higgs production, we find that the b b¯¯ γγ (σ(pp → H → hh) ∈ [81.27, 14.45] fb for mH ∈ [300, 600] GeV at 95% C.L.) and b b¯¯ b b¯¯ ([5.4, 2.5] fb for mH ∈ [800, 1000] GeV at 95% C.L.) channels are the most constraining. For the b b¯¯ H channel, we can exclude σ(pp → b b¯¯ H) ∈ [22.2, 3.7] fb for mH ∈ [300, 500] GeV. Finally, we consider the phenomenological Minimal Supersymmetric Standard Model as an example and impose various present constraints and our future direct search-limits and obtain strong constraints on the mA − tan β parameter space, where mA and tan β are respectively the mass of the pseudoscalar and the ratio of the vacuum expectation values of the two Higgs doublets. Assuming that the heavy Higgs boson decays only to Standard Model (SM) states, we find that the H → hh → b b¯¯ γγ (H → t t¯ ) channel excludes tan β as low as 4 (mA ∈ [400,800]GeV) at 95% CL. This weakens up to ∼ 5.5 when the b b¯¯ H channel dominates. Upon allowing for non-SM decay modes, the limits weaken

Scope of strongly self-interacting thermal WIMPs in a minimal U(1)DU(1)_D extension and its future prospects

In this work we have considered a minimal extension of Standard Model by a local $U(1)$ gauge group in order to accommodate a stable (fermionic) Dark Matter (DM) candidate. We have focussed on parameter regions where DM possesses adequate self interaction, owing to the presence of a light scalar mediator (the dark Higgs), alleviating some of the tensions in the small-scale structures. We have studied the scenario in the light of a variety of data, mostly from dark matter direct searches, collider searches and flavour physics experiments, with an attempt to constrain the interactions of the standard model (SM) particles with the ones in the Dark Sector (DS). Assuming a small gauge kinetic mixing parameter, we find that for rather heavy DM %$\gtrsim \mathcal{O}(1-10)\,\, {\rm GeV}$%, the most stringent bound on the mixing angle of the Dark Higgs with the SM Higgs boson comes from dark matter direct detection experiments, while for lighter DM, LHC constraints become more relevant. Note that, due to the presence of very light mediators the usual realisation of direct detection constraints in terms of momentum independent cross sections had to be reevaluated for our scenario. In addition, we find that the smallness of the relevant portal couplings, as dictated by data, critically suppress the viability of DM production by the standard "freeze-out" mechanism in such simplified scenarios. In particular, the viable DM masses are $\lesssim \mathcal{O}(2)$ GeV $i.e.$ in the regions where direct detection limits tend to become weak. For heavier DM with large self-interactions, we hence conclude that non-thermal production mechanisms are favoured. Lastly, future collider reach of such a simplified scenario has also been studied in detail.Comment: 63 pages, 21 figures, 7 table

Long live The NMSSM!

We analyze the scenario within the Next to Minimal Supersymmetric Standard Model (NMSSM), where the lightest supersymmetric particle (LSP) is singlino-like neutralino. By systematically considering various possible admixtures in the electroweakino sector, we classify regions of parameter space where the next to lightest supersymmetric particle (NLSP) is a long-lived electroweakino while remaining consistent with constraints from flavor physics, dark matter direct detection, and collider data. We identify viable cascade decay modes featuring the long-lived NLSP for directly produced chargino-neutralino pairs, thus, leading to displaced vertex signatures at the high luminosity LHC (HL-LHC). We construct track based analysis in order to uncover such scenarios at the HL-LHC and analyze their discovery potential. We show that through such focused searches for the long-lived particles at the HL-LHC, one can probe regions of the electroweakino parameter space that are otherwise challenging.Comment: 34 pages, 11 figures, 3 table

Machine learning the Higgs boson-top quark CP phase

We explore the direct Higgs boson-top CP measurement via the $pp → t\bar{t}h$ channel at the high-luminosity LHC. We show that a combination of machine learning techniques and efficient kinematic reconstruction methods can boost new physics sensitivity, effectively probing the complex $t\bar{t}h$ multiparticle phase space. Special attention is devoted to top quark polarization observables, uplifting the analysis from a raw rate to a polarization study. Through a combination of hadronic, semileptonic, and dileptonic top pair final states in association with $h→γγ$, we obtain that the HL-LHC can probe the Higgs boson-top coupling modifier and CP phase, respectively, up to $|κ_t|≲8$ at $68$ C.L