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 ρtt and ρtc offer new avenues to discover the extra scalar H 0 and pseudoscalar A 0 . We propose to search for cg → tH 0 , tA 0 followed by H 0 , A 0 → tt, tc, 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.

We present a simple U(1)B 3 −3Lµ gauge Standard Model extension that can easily account for the anomalies in R(K) and R(K * ) reported by LHCb. The model is economical in its setup and particle content. Among the Standard Model fermions, only the third generation quark family and the second generation leptons transform non-trivially under the new U(1)B 3 −3Lµ symmetry. This leads to lepton non-universality and flavor changing neutral currents involving the second and third quark families. We discuss the relevant experimental constraints and some implications.These observations are also in tune with the so called P 5 anomaly observed in the angular variable P 5 of B → K * µ + µ − decays [3][4][5][6]. In addition to these, LHCb has also observed other several other anomalies all involving b → s * cesar.bonilla@tum.de †

It was shown recently that, in two Higgs doublet models without Z2 symmetry, extra Yukawa couplings such as ρtc, ρtt can fuel enough CP violation for electroweak baryogenesis (EWBG). We revisit an old proposal where a pseudoscalar A 0 has mass between tc and tt thresholds. With ρtt small, it evades gg → 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 cg → tA 0 → ttc can probe sizable ρtc at the LHC, giving access to the second mechanism of EWBG provided by such models.

We consider a scenario in which an extra bottom Yukawa coupling can drive electroweak baryogenesis in the general two-Higgs doublet model. It is found that the new bottom Yukawa coupling with O(0.1) in magnitude can generate the sufficient baryon asymmetry without conflicting existing data. We point out that future measurements of the bottom Yukawa coupling at High-Luminosity Large Hadron Collider and International Linear Collider, together with the CP asymmetry of B → Xsγ at SuperKEKB provide exquisite probes for this scenario.

Multi-top quark production is a staple program at the LHC. Single-top and tt 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 Z2 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 tt 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.

In the general Higgs portal-like models, the extra neutral scalar, S, can mix with the Standard Model (SM) Higgs boson, H. We perform an exploratory study focusing on the direct search for such a light singlet S at the Large Hadron Collider (LHC). After careful study of the SM background, we find the process pp → ttS followed by S → bb can be used to investigate S with mass in the 20 < M S < 100 GeV range, which has not been well explored at the LHC. The signal significance becomes meaningful with a luminosity around a few ab −1 . Also, we study the prospects of finding the light scalar at the future 100 TeV pp collider, the Z and Higgs factories. With similar luminosity, the current Large Electron-Positron Collider (LEP) limits on the mixing between S and H can be improved by at least one or two order of magnitudes.

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The [Formula: see text] boson, discovered only in 2012, is lower than the top quark in mass, hence [Formula: see text] search commenced immediately thereafter, with current limits at the per mille level and improving. As the [Formula: see text] rate vanishes with the [Formula: see text]-[Formula: see text] mixing angle [Formula: see text], we briefly review the collider probes of the top changing [Formula: see text] coupling [Formula: see text] of the exotic [Formula: see text]-even/odd Higgs bosons [Formula: see text]. Together with an extra top conserving [Formula: see text] coupling [Formula: see text], one has an enhanced [Formula: see text] coupling alongside the familiar [Formula: see text] coupling, where [Formula: see text] is the charged Higgs boson. The main processes we advocate are [Formula: see text], [Formula: see text] (same-sign top and triple-top), and [Formula: see text]. We also discuss some related processes such as [Formula: see text], [Formula: see text] that depend on [Formula: see text] being nonzero, comment briefly on [Formula: see text] resonant production and touch upon the [Formula: see text] coupling.