Conveners
BSM collider physics
- Chair: Monika Blanke (KIT)
BSM collider physics
- Chair: Martin Lang (Department of Physics)
BSM collider physics
- Chair: Monika Blanke
The large top quark samples in top quark pair and single top production have yielded measurements of the production cross section of unprecedented precision and in new kinematic regimes. They have also enabled new measurements of top quark properties that were previously inaccessible, enabled the observation of many rare top quark production processes predicted by the Standard Model and...
Many theories beyond the Standard Model (BSM) have been proposed to address several of the Standard Model shortcomings, such as the origin of dark matter and neutrino masses, the fine-tuning of the Higgs boson mass, or the observed pattern of masses and mixing angles in the quark and lepton sectors. Many of these BSM extensions predict new particles or interactions directly accessible at the...
The Weinberg model is a Z_2\times Z_2-symmetric
three-Higgs-doublet model (3HDM)} designed to accommodate CP violation in the
scalar sector within a gauge theory, while at the same time allowing for natural
flavour conservation. In this model the coefficients of the potential are taken to be
complex and therefore CP is explicitly violated. With coefficients chosen to be real,
CP can be...
Models with an extended scalar electroweak sector can have vanishing vacuum expectation values. Such behaviour is a result of an underlying symmetry. If a symmetry prevents couplings between fermions and additional scalars, such scalars could become viable dark matter candidates. We catalogue $S_3$-symmetric three-Higgs-doublet models, based on whether a specific model could possibly...
We explore the discovery potential for long-lived particles at
the 250-GeV ILC. The goal is to investigate possible gains of a dedicated far
detector over the main detector ILD. For concreteness, we perform our study for
sub-GeV axion-like particles $a$ produced via $e^+e^- \to a \gamma$ or $e^+e^-
\to Z \gamma \to (a\gamma)\gamma$ and decaying into pairs of charged leptons.
In the ideal case...
The discovery of the Higgs boson with the mass of 125 GeV confirmed the mass generation mechanism via spontaneous electroweak symmetry breaking and completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many experimental measurements, it is not capable of solely explaining some observations. Many extensions of the Standard...
Very detailed measurements of Higgs boson properties can be performed with the Run 2 13 TeV pp collision dataset collected by the ATLAS experiment. This talk presents a review of the latest measurements of the Higgs boson properties, including its mass, CP, and differential cross-sections. Furthermore, couplings, including self-coupling measurement using Higgs pair production, combining...
The data collected by CMS during the LHC Run 2 allow measuring many properties of the Higgs boson. We will review in this talk the recent results from CMS. They include fiducial and differential cross-section measurements, also in the STXS framework, and measurements of di-Higgs production. They can be interpreted in terms of coupling and charge-parity measurements, or in the effective field...
Recent results on the top quark sector related to the test of various discrete symmetries of the standard model will be presented. These include the search for charge asymmetries and violation of charged lepton flavor and charge-parity symmetries, conducted using proton-proton collision data collected by the CMS experiment during 2015–2018. The obtained results are compared with predictions of...
A search for charged Higgs may yield clear and direct sign
of new physics outside the realm of the Standard Model (SM). In the Two-Higgs
Doublet Model (2HDM), we investigate two of the main single charged Higgs
production channels at the Large Hadron Collider (LHC), assuming that either h or
H replicates the detected resonance at ∼ 125 GeV; we ponder the practicality of
the associated charged...
Supersymmetric Twin Higgs models allow for naturally low
electroweak scale without much fine-tuning. If the lightest supersymmetric particle
resides in the twin sector, it could be charged under the unbroken twin
electromagnetism. I will consider the twin stau as candidate for dark matter in
these class of models. All experimental constraints, including self-interaction
bounds, are satisfied...
Models of spontaneous CP violation can solve the Strong
CP problem without the need of an anomalous Peccei-Quinn symmetry. In this talk
we review the Nelson-Barr approach, quantifying a peculiar coincidence between
unrelated mass scales that these models must satisfy in order to correctly
reproduce the Standard Model quark masses and CP violation. We investigate the
compatibility between this...
Displaced events at colliders are a promising way, and in a large region of the
parameter space the only way, to test feebly interacting particles, for instance produced through freeze-in. However, if one assumes freeze-in production happens in the standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density...
High statistics measurements of light-by-light scattering, made accessible using relativistic heavy-ion beams provide a precise and unique opportunity to investigate extensions of the Standard Model, such as the presence of axion-like particles. This talk presents a series of measurements of such processes performed by the ATLAS Collaboration. New measurements of exclusive dilepton production...
