We extend heavy Higgs searches at the Large Hadron Collider for  $$H \rightarrow \tau \mu $$  <math> <mrow> <mi>H</mi> <mo>→</mo> <mi>τ</mi> <mi>μ</mi> </mrow> </math>   by CMS, and  $$H \rightarrow \tau \tau $$  <math> <mrow> <mi>H</mi> <mo>→</mo> <mi>τ</mi> <mi>τ</mi> </mrow> </math>   by ATLAS and CMS, to study discovery prospects of extra Higgs states in  $$pp \rightarrow H,A \rightarrow \tau \mu , \tau \tau $$  <math> <mrow> <mi>p</mi> <mi>p</mi> <mo>→</mo> <mi>H</mi> <mo>,</mo> <mi>A</mi> <mo>→</mo> <mi>τ</mi> <mi>μ</mi> <mo>,</mo> <mi>τ</mi> <mi>τ</mi> </mrow> </math>   with      and      final states, where  $$j_{\tau } = \pi \,, \rho \,, a_1$$  <math> <mrow> <msub> <mi>j</mi> <mi>τ</mi> </msub> <mo>=</mo> <mi>π</mi> <mspace width="0.166667em"></mspace> <mo>,</mo> <mi>ρ</mi> <mspace width="0.166667em"></mspace> <mo>,</mo> <msub> <mi>a</mi> <mn>1</mn> </msub> </mrow> </math>   and      is missing transverse energy. In a general two Higgs doublet model without  $$Z_2$$  <math> <msub> <mi>Z</mi> <mn>2</mn> </msub> </math>   symmetry, extra Yukawa couplings  $$\rho _{\tau \tau }$$  <math> <msub> <mi>ρ</mi> <mrow> <mi>τ</mi> <mi>τ</mi> </mrow> </msub> </math>   and  $$\rho _{\tau \mu }$$  <math> <msub> <mi>ρ</mi> <mrow> <mi>τ</mi> <mi>μ</mi> </mrow> </msub> </math>   can drive  $$H,A \rightarrow \tau \tau $$  <math> <mrow> <mi>H</mi> <mo>,</mo> <mi>A</mi> <mo>→</mo> <mi>τ</mi> <mi>τ</mi> </mrow> </math>   and  $$\tau \mu $$  <math> <mrow> <mi>τ</mi> <mi>μ</mi> </mrow> </math>   channels at hadron colliders, following gluon–gluon fusion production with extra  $$\rho _{tt}$$  <math> <msub> <mi>ρ</mi> <mrow> <mi>tt</mi> </mrow> </msub> </math>   couplings. The light Higgs boson h(125) is found to resemble closely the Standard Model Higgs boson; in the alignment limit of  $$\cos \gamma \rightarrow 0$$  <math> <mrow> <mo>cos</mo> <mi>γ</mi> <mo>→</mo> <mn>0</mn> </mrow> </math>   for h–H mixing, flavor changing neutral Higgs couplings such as  $$h \rightarrow \tau \mu $$  <math> <mrow> <mi>h</mi> <mo>→</mo> <mi>τ</mi> <mi>μ</mi> </mrow> </math>   are naturally suppressed, but the couplings of the heavier H is optimized by  $$\sin \gamma \rightarrow 1$$  <math> <mrow> <mo>sin</mo> <mi>γ</mi> <mo>→</mo> <mn>1</mn> </mrow> </math>  . We define various signal regions for  $$H,A \rightarrow \tau \mu $$  <math> <mrow> <mi>H</mi> <mo>,</mo> <mi>A</mi> <mo>→</mo> <mi>τ</mi> <mi>μ</mi> </mrow> </math>   and  $$\tau \tau $$  <math> <mrow> <mi>τ</mi> <mi>τ</mi> </mrow> </math>   and evaluate physics backgrounds from dominant processes with realistic acceptance cuts and tagging efficiencies. Two different studies are presented. We first perform a parton level study without any hadronization and with minimal detector smearing. We then include hadronization using PYTHIA 8.2 and fast detector simulation using DELPHES to give event level simulation. Results for  $$\sqrt{s}= 13$$  <math> <mrow> <msqrt> <mi>s</mi> </msqrt> <mo>=</mo> <mn>13</mn> </mrow> </math>   TeV appear promising, which we extend further to  $$\sqrt{s} = 14$$  <math> <mrow> <msqrt> <mi>s</mi> </msqrt> <mo>=</mo> <mn>14</mn> </mrow> </math>   TeV for the High Luminosity LHC.

Taiwan

Wei-Shu Hou

Rishabh Jain

United States

Chung Kao

Prospects for extra Higgs boson search via  $$pp\rightarrow H,A\rightarrow \tau \mu , \tau \tau $$  <math> <mrow> <mi>p</mi> <mi>p</mi> <mo>→</mo> <mi>H</mi> <mo>,</mo> <mi>A</mi> <mo>→</mo> <mi>τ</mi> <mi>μ</mi> <mo>,</mo> <mi>τ</mi> <mi>τ</mi> </mrow> </math>   at the high luminosity Large Hadron Collider

We study a search for the charged Higgs boson via e + e  −  → H + H  −  →   <math> <mover> <mi>c</mi> <mo>¯</mo> </mover> <mi>b</mi> <mover> <mi>c</mi> <mo>¯</mo> </mover> <mi>b</mi> </math>  $$ \overline{c}b\overline{c}b $$  at the 500 GeV ILC. In a general two Higgs doublet model without Z 2 symmetry, extra Yukawa couplings ρ  tt  and ρ  tc  can drive baryogenesis, but searches at the HL-LHC may still go empty-handed if the couplings are relatively weak. Taking   <math> <msub> <mi>m</mi> <msup> <mi>H</mi> <mo>+</mo> </msup> </msub> </math>  $$ {m}_{H^{+}} $$  ≃ m  H  ≃ m  A  ≃ 200 GeV, with ρ  tt , ρ  tc  ∼ 0.1 and no h(125)-H mixing, H + →   <math> <mi>c</mi> <mover> <mi>b</mi> <mo>¯</mo> </mover> </math>  $$ c\overline{b} $$  decay is dominant, and the   <math> <mover> <mi>c</mi> <mo>¯</mo> </mover> <mi>b</mi> <mover> <mi>c</mi> <mo>¯</mo> </mover> <mi>b</mi> </math>  $$ \overline{c}b\overline{c}b $$  final state is likely overwhelmed by QCD background at the LHC. We show that the electroweak production of H + H  −  at the ILC is discoverable with integrated luminosity of 1 ab −1. Furthermore, we show that   <math> <msub> <mi>m</mi> <msup> <mi>H</mi> <mo>+</mo> </msup> </msub> </math>  $$ {m}_{H^{+}} $$  can be extracted by requiring the two pairs of b and light jets be roughly equal in mass, without assuming the mass value. Thus, ILC can probe low mass Higgs bosons in multijet final states to complement HL-LHC in the future.

Germany

Tanmoy Modak

Searching for Charged Higgs Bosons via e + e  −  → H + H  −  →   <math> <mover> <mi>c</mi> <mo>¯</mo> </mover> <mi>b</mi> <mover> <mi>c</mi> <mo>¯</mo> </mover> <mi>b</mi> </math>  $$ \overline{c}b\overline{c}b $$  at Linear Colliders

Supersymmetric models with radiatively driven naturalness enjoy low electroweak fine tuning whilst respecting LHC search limits on gluinos and top squarks and allowing for <math><msub><mi>m</mi><mi>h</mi></msub><mo>≃</mo><mn>125</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. While the heavier Higgs bosons <math><mi>H</mi></math> and <math><mi>A</mi></math> may have TeV-scale masses, the supersymmetry (SUSY)-conserving <math><mi>μ</mi></math> parameter must lie in the few hundred GeV range. Thus, in natural SUSY models there should occur large heavy Higgs boson branching fractions to electroweakinos, with Higgs boson decays to Higgsino plus gaugino dominating when they are kinematically accessible. These SUSY decays can open up new avenues for discovery. We investigate the prospects of discovering heavy neutral Higgs bosons <math><mi>H</mi></math> and <math><mi>A</mi></math> decaying into light plus heavy chargino pairs which can yield a four isolated lepton plus missing transverse energy signature at the LHC and at a future 100 TeV <math><mi>p</mi><mi>p</mi></math> collider. We find that the discovery of heavy Higgs decay to electroweakinos via its <math><mn>4</mn><mo>ℓ</mo></math> decay mode is very difficult at HL-LHC. For FCC-<math><mi>h</mi><mi>h</mi></math> or SPPC, we study the <math><mi>H</mi><mo>,</mo><mi>A</mi><mo>→</mo><mi>SUSY</mi></math> reaction along with dominant physics backgrounds from the Standard Model and devise suitable selection requirements to extract a clean signal for FCC-<math><mi>h</mi><mi>h</mi></math> or SPPC with <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>100</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, assuming an integrated luminosity of <math><mrow><mn>15</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>ab</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. We find that while a conventional cut-and-count analysis yields a signal statistical significance greater than <math><mn>5</mn><mi>σ</mi></math> for <math><msub><mi>m</mi><mrow><mi>A</mi><mo>,</mo><mi>H</mi></mrow></msub><mo>∼</mo><mn>1.1</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi><mo>−</mo><mn>1.65</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, a boosted decision-tree analysis allows for heavy Higgs signal discovery at FCC-<math><mi>h</mi><mi>h</mi></math> or SPPC for <math><msub><mi>m</mi><mrow><mi>A</mi><mo>,</mo><mi>H</mi></mrow></msub><mo>∼</mo><mn>1</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi><mo>−</mo><mn>2</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>.

Howard Baer

Vernon Barger

Dibyashree Sengupta

Xerxes Tata

Detecting heavy Higgs bosons from natural SUSY at a 100 TeV hadron collider

Recent progress on muon <math><mi>g</mi><mo>−</mo><mn>2</mn></math> measurement prompts one to take it even more seriously. In the general two Higgs doublet model that allows extra Yukawa couplings, we take a simplified approach of single enhanced coupling. We fix the charged lepton flavor violating coupling, <math><msub><mi>ρ</mi><mrow><mi>τ</mi><mi>μ</mi></mrow></msub><mo>=</mo><msub><mi>ρ</mi><mrow><mi>μ</mi><mi>τ</mi></mrow></msub></math>, via the one-loop mechanism, for illustrative masses of the heavy scalar <math><mi>H</mi></math> and pseudoscalar <math><mi>A</mi></math>, where we assume <math><msub><mi>m</mi><mi>A</mi></msub><mo>=</mo><msub><mi>m</mi><msup><mi>H</mi><mo>+</mo></msup></msub></math>. Since extra top Yukawa couplings are plausibly the largest, we turn on <math><msub><mi>ρ</mi><mrow><mi>t</mi><mi>t</mi></mrow></msub></math> and find that LHC search for <math><mi>g</mi><mi>g</mi><mo>→</mo><mi>H</mi><mo>,</mo><mi>A</mi><mo>→</mo><mi>τ</mi><mi>μ</mi></math> gives a more stringent bound than from <math><mi>τ</mi><mo>→</mo><mi>μ</mi><mi>γ</mi></math> with the two-loop mechanism. Turning on a second extra top Yukawa coupling, <math><msub><mi>ρ</mi><mrow><mi>t</mi><mi>c</mi></mrow></msub></math>, can loosen the bound on <math><msub><mi>ρ</mi><mrow><mi>t</mi><mi>t</mi></mrow></msub></math>, but LHC constraints can again be more stringent than from <math><mi>B</mi><mo>→</mo><mi>D</mi><mi>μ</mi><mi>ν</mi></math> versus <math><mi>D</mi><mi>e</mi><mi>ν</mi></math> universality. This means that evidence for <math><mi>H</mi><mo>,</mo><mi>A</mi><mo>→</mo><mi>τ</mi><mi>μ</mi></math> may yet emerge with full LHC Run 2 data, while direct search for <math><msup><mi>τ</mi><mo>±</mo></msup><msup><mi>μ</mi><mo>∓</mo></msup><mi>b</mi><msup><mi>W</mi><mo>+</mo></msup></math> or <math><mi>t</mi><mover><mi>c</mi><mo>¯</mo></mover><mi>b</mi><msup><mi>W</mi><mo>+</mo></msup></math> (plus conjugate) may also bear fruit.

Girish Kumar

Collider prospects for the muon <math><mi>g</mi><mo>−</mo><mn>2</mn></math> in a general two-Higgs-doublet model

We investigate the prospects of discovering the top-quark decay into a charm quark and a Higgs boson (<math><mi>t</mi><mo>→</mo><mi>c</mi><msup><mi>h</mi><mn>0</mn></msup></math>) in top-quark pair production at the CERN Large Hadron Collider (LHC). A general two-Higgs-doublet model is adopted to study flavor-changing neutral Higgs (FCNH) interactions. We perform a parton-level analysis as well as Monte Carlo simulations using Pythia 8 and Delphes to study the flavor-changing top-quark decay <math><mrow><mi>t</mi><mo>→</mo><mi>c</mi><msup><mrow><mi>h</mi></mrow><mrow><mn>0</mn></mrow></msup></mrow></math>, followed by the Higgs decaying into <math><msup><mi>τ</mi><mo>+</mo></msup><msup><mi>τ</mi><mo>−</mo></msup></math>, with the other top quark decaying to a bottom quark (<math><mi>b</mi></math>) and two light jets (<math><mrow><mi>t</mi><mo>→</mo><mi>b</mi><mi>W</mi><mo>→</mo><mi>b</mi><mi>j</mi><mi>j</mi></mrow></math>). To reduce the physics background to the Higgs signal, only the leptonic decays of tau leptons are considered, <math><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>e</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>∓</mo></mrow></msup><mo>+</mo><msub><mrow><mrow><mi>E</mi></mrow></mrow><mrow><mi>T</mi></mrow></msub></mrow></math>, where <math><msub><mi>E</mi><mi>T</mi></msub></math> represents the missing transverse energy from the neutrinos. In order to reconstruct the Higgs boson and top-quark masses as well as to reduce the physics background, the collinear approximation for the highly boosted tau decays is employed. Furthermore, the energy distribution of the charm quark helps set the acceptance criteria used to reduce the background and improve the statistical significance of the signal. We study the discovery potential for the FCNH top decay at the LHC with collider energy <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn></math> and 14 TeV as well as a future hadron collider with <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>27</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>. Our analysis suggests that a high-energy LHC at <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>27</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> will be able to discover this FCNH signal with an integrated luminosity <math><mrow><mi>L</mi><mo>=</mo><mn>3</mn><mtext> </mtext><mtext> </mtext><mrow><msup><mrow><mi>ab</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></mrow></math> for a branching fraction <math><mrow><mi>B</mi><mo>(</mo><mi>t</mi><mo>→</mo><mi>c</mi><msup><mrow><mi>h</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>)</mo><mo>≳</mo><mn>1.4</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></math>, which corresponds to a FCNH coupling <math><mrow><mo>|</mo><msub><mrow><mi>λ</mi></mrow><mrow><mi>t</mi><mi>c</mi><mi>h</mi></mrow></msub><mo>|</mo><mo>≳</mo><mn>0.023</mn></mrow></math>. This FCNH coupling is significantly below the current ATLAS combined upper limit of <math><mo>|</mo><msub><mi>λ</mi><mrow><mi>t</mi><mi>c</mi><mi>h</mi></mrow></msub><mo>|</mo><mo>=</mo><mn>0.064</mn></math>.

Phillip Gutierrez

Flavor changing top decays to charm and a Higgs boson with <math><mi>τ</mi><mi>τ</mi></math> at the LHC

In a general two Higgs doublet model, we study flavor changing neutral Higgs (FCNH) decays into leptons at hadron colliders, <math><mi>p</mi><mi>p</mi><mo>→</mo><msup><mrow><mi>ϕ</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>→</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>∓</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>±</mo></mrow></msup><mo>+</mo><mi>X</mi></math>, where <math><msup><mrow><mi>ϕ</mi></mrow><mrow><mn>0</mn></mrow></msup></math> could be a CP-even scalar (<math><msup><mrow><mi>h</mi></mrow><mrow><mn>0</mn></mrow></msup></math>, <math><msup><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msup></math>) or a CP-odd pseudoscalar (<math><msup><mrow><mi>A</mi></mrow><mrow><mn>0</mn></mrow></msup></math>). The light Higgs boson <math><msup><mrow><mi>h</mi></mrow><mrow><mn>0</mn></mrow></msup></math> is found to resemble closely the Standard Model Higgs boson at the Large Hadron Collider. In the alignment limit of <math><mi>cos</mi><mo>⁡</mo><mo>(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo>)</mo><mo>≅</mo><mn>0</mn></math> for <math><msup><mrow><mi>h</mi></mrow><mrow><mn>0</mn></mrow></msup></math>–<math><msup><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msup></math> mixing, FCNH couplings of <math><msup><mrow><mi>h</mi></mrow><mrow><mn>0</mn></mrow></msup></math> are naturally suppressed, but such couplings of the heavier <math><msup><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>,</mo><msup><mrow><mi>A</mi></mrow><mrow><mn>0</mn></mrow></msup></math> are sustained by <math><mi>sin</mi><mo>⁡</mo><mo>(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo>)</mo><mo>≃</mo><mn>1</mn></math>. We evaluate physics backgrounds from dominant processes with realistic acceptance cuts and tagging efficiencies. We find promising results for <math><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>14</mn><mtext> TeV</mtext></math>, which we extend further to <math><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>27</mn><mtext> TeV</mtext></math> and 100 TeV future pp colliders.

Masaya Kohda

Brent McCoy

Amarjit Soni

Flavor changing heavy Higgs interactions with leptons at hadron colliders

We investigate the prospects for discovering a top quark decaying into one light Higgs boson (<math><msup><mi>h</mi><mn>0</mn></msup></math>) along with a charm quark (<math><mi>c</mi></math>) in top-quark pair production at the CERN LHC and future hadron colliders. A general two Higgs doublet model is adopted to study the signature of flavor changing neutral Higgs interactions with <math><mi>t</mi><mo>→</mo><mi>c</mi><msup><mi>h</mi><mn>0</mn></msup></math>, followed by <math><msup><mi>h</mi><mn>0</mn></msup><mo>→</mo><mi>W</mi><msup><mi>W</mi><mo>*</mo></msup><mo>→</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup><mo>+</mo><msub><mi>E</mi><mi>T</mi></msub></math>, where <math><msup><mi>h</mi><mn>0</mn></msup></math> is the <math><mi>C</mi><mi>P</mi></math>-even Higgs boson and <math><msub><mi>E</mi><mi>T</mi></msub></math> stands for missing transverse energy from neutrinos. We study the discovery potential for this flavor changing neutral Higgs signal and physics background from dominant processes with realistic acceptance cuts as well as tagging and mistagging efficiencies. Promising results are found for the LHC running at 13 and 14 TeV center-of-mass energy as well as future pp colliders at 27 and 100 TeV.

Charming top decays with a flavor changing neutral Higgs boson and <math><mi>W</mi><mi>W</mi></math> at hadron colliders

Corda, Mosquera Cuesta, and Lorduy Gòmez have shown that spherically symmetric stationary states can be used as a model for galaxies in the framework of the linearized <math id="M2"><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math> gravity. Those states could represent a partial solution to the Dark Matter Problem. Here, we discuss an improvement of this work. In fact, as the star density is a functional of the invariants of the associated Vlasov equation, we show that any of these invariants is in its turn a functional of the local energy and the angular momentum. As a consequence, the star density depends only on these two integrals of the Vlasov system. This result is known as the “Jeans theorem.” In addition, we find an analogy of the historical Tolman–Oppenheimer–Volkoff equation for the system considered in this paper. For the sake of completeness, in the final section of the paper, we consider two additional models which argue that Dark Matter could not be an essential element.