Search

We study a search for the charged Higgs boson via e+e−→ H+H−→ c ¯ b c ¯ b at the 500 GeV ILC. In a general two Higgs doublet model without Z2 symmetry, extra Yukawa couplings ρtt and ρtc can drive baryogenesis, but searches at the HL-LHC may still go empty-handed if the couplings are relatively weak. Taking m H + ≃ mH ≃ mA ≃ 200 GeV, with ρtt, ρtc ∼ 0.1 and no h(125)-H mixing, H+ → c b ¯ decay is dominant, and the c ¯ b 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 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. [ABSTRACT FROM AUTHOR]

β‐Alkynyl substituted γ,γ‐difluoroallyl‐boronates were prepared via defluorination under basic condition. Allylation reaction of aldehydes with gem‐difluoroallylboronates under metal‐free condition in water was developed. As the sole solvent, water dramatically improved the efficiency of the reaction, and afforded the desired products in 48–92% yields. The corresponding difluorinated alcohols were smoothly transformed into the 3,3‐difluoro‐4‐methylene‐3,4‐dihydro‐2H‐pyran derivatives in the presence of gold catalyst. [ABSTRACT FROM AUTHOR]

The h (1 2 5) boson, discovered only in 2012, is lower than the top quark in mass, hence t → c h search commenced immediately thereafter, with current limits at the per mille level and improving. As the t → c h rate vanishes with the h - H mixing angle cos γ → 0 , we briefly review the collider probes of the top changing t c H / t c A coupling ρ t c of the exotic C P -even/odd Higgs bosons H / A. Together with an extra top conserving t t H / t t A coupling ρ t t , one has an enhanced c b H + coupling alongside the familiar t b H + coupling, where H + is the charged Higgs boson. The main processes we advocate are c g → t H / A → t t c ̄ , t t t ̄ (same-sign top and triple-top), and c g → b H + → b t b ̄. We also discuss some related processes such as c g → t h h , t Z H that depend on cos γ being nonzero, comment briefly on g g → H / A → t t ̄ , t c ̄ resonant production and touch upon the ρ t u coupling. [ABSTRACT FROM AUTHOR]

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

Abstract It was shown recently that, in two Higgs doublet models without Z 2 symmetry, extra Yukawa couplings such as ρ t c , ρ t t can fuel enough CP violation for electroweak baryogenesis (EWBG). We revisit an old proposal where a pseudoscalar A 0 has mass between t c ¯ and t t ¯ thresholds. With ρ t t small, it evades g g → A 0 → h 0 (125) Z constraints, where approximate alignment also helps. We find this scenario with relatively light A 0 is not yet ruled out, and c g → t A 0 → t t c ¯ can probe sizable ρ t c at the LHC, giving access to the second mechanism of EWBG provided by such models. [ABSTRACT FROM AUTHOR]

We study electroweak baryogenesis driven by the top quark in a general two Higgs doublet model with flavor-changing Yukawa couplings, keeping the Higgs potential CP invariant. With Higgs sector couplings and the additional top Yukawa coupling ρ t t all of O (1), one naturally has sizable CP violation that fuels the cosmic baryon asymmetry. Even if ρ t t vanishes, the favor-changing coupling ρ t c can still lead to successful baryogenesis. Phenomenological consequences such as t → c h , τ → μ γ electron electric dipole moment, h → γ γ , and hhh coupling are discussed. [ABSTRACT FROM AUTHOR]

The B s → μ + μ − mode has finally been observed, albeit at rate 1.2 σ below Standard Model (SM) value, while the rarer B d 0 → μ + μ − decay has central value close to 4 times SM expectation but with only 2.2 σ significance. The measurement of CP violating phase ϕ s has finally reached SM sensitivity. Concurrent with improved measurements at LHC Run 2, K L → π 0 ν ν ¯ and K + → π + ν ν ¯ decays are being pursued in a similar time frame. We find, whether B d 0 → μ + μ − is enhanced or not, K L → π 0 ν ν ¯ can be enhanced up to the Grossman–Nir bound in the fourth generation model, correlated with some suppression of B s → μ + μ − , and with ϕ s remaining small. [ABSTRACT FROM AUTHOR]

A general two Higgs doublet model (2HDM) is adopted to study the signature of flavor changing neutral Higgs (FCNH) decay ϕ 0 → t c ¯ + t ¯ c , where ϕ 0 could be a CP-even scalar ( H 0 ) or a CP-odd pseudoscalar ( A 0 ). Measurement of the light 125 GeV neutral Higgs boson ( h 0 ) couplings at the Large Hadron Collider (LHC) favor the decoupling limit or the alignment limit of a 2HDM, in which gauge boson and diagonal fermion couplings of h 0 approach Standard Model values. In such limit, FCNH couplings of h 0 are naturally suppressed by a small mixing parameter cos ⁡ ( β − α ) , while the off-diagonal couplings of heavier neutral scalars ϕ 0 are sustained by sin ⁡ ( β − α ) ∼ 1 . We study physics background from dominant processes with realistic acceptance cuts and tagging efficiencies. Promising results are found for the LHC running at 13 or 14 TeV collision energies. [ABSTRACT FROM AUTHOR]

Abstract: The newly discovered “Higgs” boson , being lighter than the top quark t, opens up new probes for flavor and mass generation. In the general two Higgs doublet model, new ct, cc and tt Yukawa couplings could modify properties. If occurs at the percent level, the observed and γγ signal events may have accompanying cbW activity coming from feeddown. We suggest that can be searched for via , γγ, and , perhaps even modes in events. Existing data might be able to reveal some clues for signature, or push the branching ratio down to below the percent level. [Copyright &y& Elsevier]

We consider the so-called "eV seesaw" scenario, with right-handed Majorana mass MR at eV order, extended to four lepton generations. The fourth generation gives a heavy pseudo-Dirac neutral lepton, which largely decouples from other generations and is relatively stable. The framework naturally gives three active and three sterile neutrinos. We update a previous numerical analysis of a 3+3 study of the LSND anomaly, taking into account the more recent results from the MiniBooNE experiment. In particular, we study the implications for the third mixing angle sin2 θ13, as well as CP violation. We find that current data do not seriously constrain more than one sterile neutrinos. [ABSTRACT FROM AUTHOR]

Abstract: We extend the eV seesaw scenario to four lepton generations. The LSND anomaly is taken as the right-handed seesaw scale, i.e., . The fourth generation then gives a heavy pseudo-Dirac neutrino which largely decouples from other generations, and is relatively stable. One effectively has a solution to the LSND anomaly, where we illustrate with numerical solutions. Our study seems to indicate that the third mixing angle may be less than 0.01. [Copyright &y& Elsevier]

The highlights and conflicts at the B factories are briefly reviewed. CP violation was established in 2001 in B0→J/ψKS and related modes, which has now become a precision measurement of CP violation in $B^0$--$\bar B^0$ mixing. However, the situation for the B0→π+π- and charmless b→s modes, which also probe CP violation in the decay amplitude, are not quite settled yet. They could be hinting at the presence of both strong (CP conserving) and new physics (CP violating) phases. We critically assess the developments and discuss some related discrepancies and highlights, such as observation of direct CP violation, and make a projection towards the next few years. [ABSTRACT FROM AUTHOR]

The Ds(2320) state recently observed by BaBar in the Ds+π0 channel may be the first of a host of cqq¯q¯ four-quark states. We give a phenomenological account of the masses and decay modes. The isosinglet Ds(2320) state is the only narrow one, dominated by the observed isospin violating decay and less than ∼ 100 keV in width. All other states are expected to decay hadronically. Notable resonances are in doubly charged Ds+π+, D+K+, wrong pairing D+K−, and also Ds+K−, Dη channels. We propose B decays as searching ground for such 4-quark states, which recoil against D¯(*) meson from B decay, or π+ D¯(*), K¯ mesons from B¯ decay. Exotic qcc¯q¯ charmonia could also be produced, and may be behind the slow J/ψ bump in inclusive B→J/ψ+X decay. [Copyright &y& Elsevier]

Recent data on B→pp¯K, K0ππ and KKK hint at a ∼2.3 GeV object recoiling against a kaon. This could be the narrow state observed in J/ψ→γξ. Nonobservation in pp¯ annihilation implies B(ξ→pp¯)∼ few ×10−3, consistent with ηc and J/ψ decays, but there are actual hints in pp¯→φφ and pp→pπ+π−π+π−p. Simple modeling shows B(B→ξK)B(ξ→pp¯)∼1×10−6, appearing as a spike in the pp¯ spectrum, with ∼ 30 events per 100 fb−1; modes such as KKsKs, Kφφ, K4π (Kf2ππ) etc. should be explored. The underlying dynamics of g*→gξ is analogous to g*→gη′ or gluon fragmentation. Discovery of sizable B→ξK could be useful for CP violation studies. [Copyright &y& Elsevier]

We predict the rates of the charmless three-body B0→ρ−pn¯ and π−pn¯ modes due to weak vector current contributions to be ∼4×10−6 and 2×10−6, respectively. The basis is a factorization approach of current produced nucleon pairs, together with an isospin transformation that relates nucleon weak vector form factors to electromagnetic form factors. Adding the axial vector current contribution, we find B0→ρ−pn¯ and B+→ρ0pn¯ to be at 10−5 order. The three-body modes appear to dominate over the two-body modes such as B→pp¯, pΛ¯. [Copyright &y& Elsevier]

With no New Physics seen at the LHC, a second Higgs doublet remains attractive and plausible. The ratio R B μ / τ = B (B → μ ν ¯) / B (B → τ ν ¯) is predicted at 0.0045 in both the Standard Model and the two Higgs doublet model type II, but it can differ if extra Yukawa couplings exist in Nature. Considering recent Belle update on B → μ ν ¯ , the ratio could be up by a factor of two in the general two Higgs doublet model, which can be probed by the Belle II experiment with just a few ab−1. [ABSTRACT FROM AUTHOR]

Multi-top quark production is a staple program at the LHC. Single-top and t t ¯ productions are studied extensively, while current efforts are zooming in on four-top search, where the Standard Model (SM) cross section is at O (10) fb. In contrast, only at the fb level in SM, triple-top production has not been targeted for study so far. But such a small cross section makes it a unique probe for New Physics. Without the usual discrete Z 2 symmetry, the general two Higgs doublet model (g2HDM) can naturally raise the triple-top production to pb level. We illustrate how certain signal regions of four-top search can be utilized to constrain triple-top production, but urge a dedicated search. As an aside, we note that the CMS study at 13 TeV of scalar t t ¯ resonance interfering with QCD production background indicate some activity at 400 GeV. We comment that this could be explained in principle in g2HDM via the extra top Yukawa coupling. [ABSTRACT FROM AUTHOR]

The 125 GeV boson is quite consistent with the Higgs boson of the Standard Model (SM), but there is a challenge from Anderson as to whether this particle is in the Lagrangian. As Large Hadron Collider (LHC) Run 2 enters its final year of running, we ought to reflect and make sure we have gotten everything right. The ATLAS and CMS combined Run 1 analysis claimed a measurement of 5.4 σ vector boson fusion (VBF) production which is consistent with SM, which seemingly refutes Anderson. However, to verify the source of electroweak symmetry breaking (EWSB), we caution that VBF measurement is too important for us to be imprudent in any way, and gluon–gluon fusion (ggF) with similar tag jets must be simultaneous measured, which should be achievable in LHC Run 2. The point is to truly test the dilaton possibility—the pseudo-Goldstone boson of scale invariance violation. We illustrate EWSB by dynamical mass generation of a sequential quark doublet (Q) via its ultrastrong Yukawa coupling and argue how this might be consistent with a 125 GeV dilaton, D. The ultraheavy 2 m Q ≳ 4 –5 TeV scale explains the absence of New Physics so far, while the mass generation mechanism shields us from the UV theory for the strong Yukawa coupling. Collider and flavor physics implications are briefly touched upon. Current Run 2 analyses show correlations between the ggF and VBF measurements, but the newly observed t t ¯ H production at LHC poses a challenge. [ABSTRACT FROM AUTHOR]

The alignment phenomenon, that the 125 GeV h 0 boson so resembles the Standard Model Higgs boson, can be understood in a two Higgs doublet model without discrete symmetry. New Yukawa couplings ρ t t and ρ t c offer new avenues to discover the extra scalar H 0 and pseudoscalar A 0 . We propose to search for c g → t H 0 , t A 0 followed by H 0 , A 0 → t t ¯ , t c ¯ , where same-sign dileptons could be the harbinger, with triple-top, in the signature of three leptons plus three b -jets, as confirmation. Discovery could touch upon the origin of baryon asymmetry of the Universe. [ABSTRACT FROM AUTHOR]

Abstract: We investigate the prospects for discovering a top quark decaying into one light Higgs boson along with a charm quark in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study the signature of flavor changing neutral Higgs decay , where could be CP-even () or CP-odd (). The dominant physics background is evaluated with realistic acceptance cuts as well as tagging and mistagging efficiencies. For a reasonably large top–charm–Higgs coupling (), the abundance of signal events and the reduction in physics background allow us to establish a 5σ signal for at the LHC with a center of mass energy of 8 TeV and an integrated luminosity of 20 fb−1. The discovery potential will be greatly enhanced with the full energy of . [Copyright &y& Elsevier]