Conveners
Physics Beyond the Standard Model: SUSY searches at the LHC
- Zhen Liu
Physics Beyond the Standard Model: SUSY and SMEFT
- Kirtimaan Ajaykant Mohan
Physics Beyond the Standard Model: LHC Search Results
- Ian Lewis (The University of Kansas)
Physics Beyond the Standard Model: Neutrinos, Leptogenesis and Baryogenesis
- Christopher Cappiello
Physics Beyond the Standard Model: Charged Higgs Searches
- Prudhvi Bhattiprolu (University of Michigan)
Physics Beyond the Standard Model: Strong CP Problem and Hidden Valleys
- Ben Lillard (University of Oregon)
Physics Beyond the Standard Model: Holography, Extra-Dimensions & Amplitudes
- Zhengkang Zhang (University of Utah)
Physics Beyond the Standard Model: Long lived particles at colliders
- Carlos Henrique de Lima (Carleton University)
Physics Beyond the Standard Model: Neutrino Masses and Dark Matter
- Qinrui Liu (Queen's University)
Physics Beyond the Standard Model: Collider Physics: current and future
- Wolfram Ratzinger (Weizmann Institute)
Supersymmetry is an appealing theoretical extension of the Standard Model because this framework presents a viable dark matter candidate. Several CMS analyses have searched for evidence of supersymmetry at the electroweak scale in the compressed region, where the parent sparticle mass is close to that of the child, leading to soft Standard Model decay products that can be difficult to...
A search is presented for the pair-production of charginos and the production of a chargino and neutralino in a supersymmetric model where the near mass-degenerate chargino and neutralino each decay via $R$-parity-violating couplings to a Higgs boson and a charged lepton or neutrino. This analysis searches for a Higgs-lepton resonance in data corresponding to an integrated luminosity of 139...
A search is presented for the direct pair production of scalar tops, which each decay through an $R$-parity violating coupling to a charged lepton and a $b$-quark. The final state has two resonances formed by the lepton-jet pairs. Expected sensitivity will be shown for the dataset consisting of an integrated luminosity of 140 $fb^{-1}$ of proton-proton collisions at a center-of-mass energy of...
In natural supersymmetric models defined by no worse than a part in
thirty electroweak fine-tuning, winos and binos are generically expected
to be much heavier than higgsinos. Moreover, the splitting between the
higgsinos is expected to be small, so that the visible decay products of
the heavier higgsinos are soft, rendering the higgsinos quasi-invisible
at the LHC. Within the natural...
We present theoretical results at approximate NNLO in QCD for top-quark pair-production total cross sections and top-quark differential distributions at the LHC in the SMEFT. These approximate results are obtained by adding higher-order soft gluon corrections to the complete NLO calculations. The higher-order corrections are large, and they reduce the scale uncertainties. These improved...
We study the implications of precise gauge coupling unification on supersymmetric particle masses. We argue that precise unification favors the superpartner masses that are in the range of several TeV and well beyond. We demonstrate this in the minimal supersymmetric theory with a common sparticle mass threshold, and two simple high-scale scenarios: minimal supergravity and minimal...
We present the basis of dimension-eight operators associated to
universal theories. We first derive a complete list of independent
dimension-eight operators formed with the Standard Model bosonic
fields characteristic of such universal new physics
scenarios. Without imposing C nor P the basis contains 175 operators
- this is, the assumption of Universality reduces the number of...
We are investigating the effects of dimension 6 dipole moment operators on dipole
moment measurements, which are electric dipole moment (EDM) and magnetic dipole moment (MDM).
Baryon number violation is our most sensitive probe of physics beyond the Standard Model. Its realization through heavy new particles can be conveniently encoded in higher-dimensional operators that allow for a model-agnostic analysis. The unparalleled sensitivity of nuclear decays to baryon number violation makes it possible to probe effective operators of very high mass dimension, far beyond...
A search for a massive resonance $X$ decaying to a pair of spin-0 bosons $\phi$ that themselves decay to pairs of photons ($\gamma$), is presented. The search is based on CERN LHC proton-proton collision data at $\sqrt{s} = 13$ TeV, collected with the CMS detector, corresponding to an integrated luminosity of 138 $\textrm{fb}^{-1}$. The analysis considers masses $m_X$ between 0.3 and 3 TeV,...
We present the first search for "soft unclustered energy patterns" (SUEPs) described by an isotropic production of many soft particles. SUEPs are a potential signature of some Hidden Valley models invoked to explain dark matter, and which can be produced at the LHC via a heavy scalar mediator. It was previously expected that such events would be rejected by conventional collider triggers and...
We present a search for low-mass narrow quark-antiquark resonances. This search uses data from the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS detector in Run 2, and corresponds to an integrated luminosity of 136 fb^-1. The analysis strategy makes use of an initial state photon recoiling against the narrow resonance. The resulting large transverse...
A search for Drell Yan production of leptoquarks is performed using proton-proton collision data collected at โs = 13 TeV using the full Run-2 dataset with the CMS detector at the LHC, CERN. The data corresponds to an integrated luminosity of approximately 137 fbโ1. The search spans scalar and vector leptoquarks that couple up and down quarks to electrons and muons. Dielectron and dimuon final...
Long-lived, charged particles are included in many beyond the standard model theories. It is possible to observe massive charged particles through unusual signatures within the CMS detector. We use data recorded during 2017-18 operations to search for signals involving anomalous ionization in the silicon tracker. Two new, enhanced methods are presented. The results are interpreted within...
Long-lived particles (LLPs) arise in many promising theories beyond the Standard Model. At the LHC, LLPs typically decay away from their initial production vertex, producing displaced and possibly delayed final state objects that give rise to non-conventional detector signatures. The development of custom reconstruction algorithms and dedicated background estimation strategies significantly...
Models of freeze-in darkmatter (DM) can incorporate baryogenesis by a straightforward extension to two or more DM particles with different masses. We study a novel realization of freeze-in baryogenesis, in which a new SU(2)-doublet vector-like fermion (VLF) couples feebly to the SM Higgs and multiple fermionic DM mass eigenstates, leading to out-of-equilibrium DM production in the early...
In this work, we explore baryon number violating interactions (BNV) within a specific model framework involving a charged iso-singlet, color-triplet scalar and a Majorana fermion with interactions in the quark sector. This model has been useful for explaining baryogenesis, neutron-antineutron oscillations, and other puzzles such as the DM-baryon coincidence puzzle. We revisit this model, with...
In the ongoing Short-Baseline Neutrino facilities such as the Short-Baseline Near Detector (SBND), MicroBooNE and ICARUS, there exists an iron dump positioned $\sim$ 45.79 m from the Fermilab Booster Neutrino Beam (BNB)โs beryllium target. The neutrinos produced from charged pion and kaon decays can undergo up-scattering off iron nuclei resulting in the production of MeV mass scale heavy...
In the context of the left-right symmetric model, we study the interplay of the neutrinoless double beta ($0\nu\beta\beta$) decay, parity-violating Mรธller scattering, and high-energy colliders, resulting from the Yukawa interaction of the right-handed doubly-charged scalar to electrons, which could evade the severe constraints from charged lepton flavor violation. The half-life $\onbb$ decay...
The discovery of the neutral Higgs Boson of mass 125 GeV by the ATLAS and CMS experiments in 2012 has prompted further discussions on whether extensions of the Standard Model (SM) scalar sector exist, other than the observed SM doublet. The two-Higgs-doublet model (2HDM) is one of such extensions predicting the additional doublets. This model is supported by Supersymmetry and could provide the...
The Standard Model provides the best description of the known fundamental particles and their interactions to date. However, findings regarding excesses of taus show a tension between Standard Model predictions and observed data. This tension can be understood in the context of a 2HDM. In this talk, I will show the recent results of the model-independent search for charged Higgs bosons via...
NelsonโBarr models, which assume that CP is a spontaneously broken symmetry of nature, are a well-known solution to the strong CP problem with no new light degrees of freedom. Nevertheless, the spontaneous breaking of CP has dramatic implications in cosmology. It was recently shown that domain walls which form from this spontaneous breaking are exactly stable and must therefore be inflated...
Our objective is to address the strong CP problem by leveraging softly broken Parity invariance within the framework of the Quark-Lepton Unified (Pati-Salam) Model, where fermions undergo the "see-saw" mass generation mechanism. The incorporation of vector-like fermions facilitates the realization of this mechanism. The smallness of the Physical Theta-parameter ($\bar{\theta}$) is attributed...
We show that in the Nelson-Barr solution to the strong CP-problem a naturally light scalar can arise. The dependence of the CKM matrix elements on this new scalar is its predominant coupling. It gives rise to a completely new phenomenology if this field constitutes dark matter, as CKM elements vary periodically in time.
We discuss dark shower signals at the LHC from a dark QCD sector, containing GeV-scale dark pions. The portal with the Standard Model is given by the mixing of the $Z$ boson with a dark $Z^\prime$ coupled to the dark quarks. Both mass and kinetic mixings are included, but the mass mixing is the essential ingredient, as it is the only one mediating visible decays of the long-lived dark pions on...
Dark-showers offer a compelling collider signature for Hidden Valley models featuring a confining dark sector. Our work extends the investigation of these models to near-conformal theories where the running coupling, controlled by renormalization group equations (RGE), flows near to an infra-red fixed point. We establish a framework of two classes of RGE solutions which cover much of the...
We consider a Hidden Valley model which generates showering from strong dynamics within the dark sector followed by decays back into Standard Model states. Our interest is the limit of smaller dark pion masses, which create a high multiplicity of final states. The reconstruction of dark sector masses in such a setting is obscured by a thick combinatoric background. We apply the new SIFT...
Many well-motivated beyond-the-standard-model (BSM) scenarios naturally predict the production of hadronically decaying long-lived particles (LLPs) at the LHC, which leads to displaced-jet signatures. A displaced-jet search is therefore a powerful tool to address numerous long-standing puzzles in particle physics. With the Run 3 at LHC that started from 2022, we have developed and deployed a...
We derive the EFT amplitudes relevant for vector-boson pair production at the LHC in the dimension-8 SMEFT using on-shell methods. Since they are directly related to physical observables, the results allow for the identification of phenomenologically interesting amplitudes, and can furthermore distinguish between the SMEFT and generic EFTs.
We perform a comprehensive analysis of the scattering of matter and gravitational Kaluza-Klein(KK) modes in five-dimensional gravity theories. We consider matter localized on a brane as well as in the bulk of the extra dimension for scalars, fermions and vectors respectively, and consider an arbitrary warped background. While naive power-counting suggests that there are amplitudes which grow...
Many scenarios beyond the standard model hypothesize the existence of new particles with long lifetimes. These long-lived particles (LLPs) decay significantly displaced from their initial production vertex, leading to unconventional signatures within the detector. This presentation focuses on searches with LLP decays within the CMS muon system. An innovative usage of the CMS muon detectors is...
In this talk, I will discuss how the residual five-dimensional diffeomorphism symmetries of compactified gravitational theories with a warped extra dimension imply Equivalence theorems which ensure that the scattering amplitudes of helicity-0 and helicity-1 spin-2 Kaluza-Klein states equal (to leading order in scattering energy) those of the corresponding Goldstone bosons present in the...
A search for long-lived particles decaying into an oppositely charged lepton pair, mumu, ee, emu, is presented with a requirement that candidate leptons form a vertex within the inner tracking volume of ATLAS, displaced from the primary pp interaction region. The analysis uses the 140 fb^-1 of Run II data collected at 13 TeV by the ATLAS Experiment in 2015-2018. The results of the analysis are...
As the field examines a future muon collider as a possible successor to the LHC, we must consider how to fully utilize not only the high-energy particle collisions, but also any lower-energy staging facilities necessary in the R&D process. An economical and efficient possibility is to use the accelerated muon beam from either the full experiment or from cooling and acceleration tests in...
The most general massless particles allowed by Poincare' invariance are โcontinuous spinโ particles (CSPs), a term coined by Wigner. Such particles are notable for their integer-spaced infinite tower of spin polarizations, with states of different integer (or half-integer) helicities mixing under boosts, much like the spin-states of a massive particle. The mixing under boosts is controlled by...
Color-sextet scalars have well-known renormalizable couplings to quark pairs, but they could have an array of other possible couplings to the Standard Model. This talk will focus on proposed LHC searches for two operators of mass dimension six which include these sextet scalars. The first of these operators involves color-sextet scalars in a channel with jets and a hard opposite-sign lepton...
We develop a grand unified theory of matter and forces based on the gauge symmetry $SU(5)_L\times SU(5)_R$ with parity interchanging the two factor groups. Our main motivation for such a construction is to realize a minimal GUT embedding of left-right symmetric models that provide a parity solution to the strong CP problem without the axion. We show how the gauge couplings unify with an...
Vector-like quarks (VLQs) are hypothetical particles that may lead to new physics phenomena, resolving the hierarchy problem. This talk presents a search for vector-like B quarks decaying into a top quark and a W boson, using the full CMS Run 2 proton-proton collision data at โs=13 TeV. The search targets single-lepton final states that contain one well-reconstructed muon or electron. The mass...
The recent observation of collider neutrinos and BSM searches by the FASER collaboration highlights the potential the forward direction at the LHC has for neutrino and BSM physics. But in these studies, the dominant background comes from muons and significant effort goes into suppressing them. In this work, we describe efforts to use these โbackgroundโ muons to study muon-philic particles. In...
Novel heavy vector resonances are a common prediction of theories beyond the Standard Model, and the framework of simplified models provides a phenomenological bridge between these theories and the experimental limits obtained at colliders. In this talk I will introduce a simplified model for two colorless heavy vector resonances in the singlet representation of $SU(2)_L$, with zero and unit...
We explore the possibility of probing new physics particles that scatter into visible particles at DarkQuest, such as neutrino tridents, Bethe-Heitler scattering, etc. The DarkQuest setup consists of a 120 GeV proton beam that impinges on a 5 m iron block with the detector placed 25 m away from the proton source. We find that the closeness of the detector to this high-energy proton source is...
Double Higgs production plays a crucial role in assessing the Higgs self-coupling (trilinear Higgs coupling), which is responsible for endowing elementary particles with mass and shaping the Higgs potential. Measuring the trilinear Higgs coupling at proton colliders necessitates high luminosity due to the rarity of processes involving it in the Standard Model. Nonetheless, muon colliders offer...
Leptogenesis can provide solutions to the baryon asymmetry of the Universe (BAU) and explain the origin of mass for SM neutrinos. In the framework of conventional thermal leptogenesis, a major obstacle arises from the strong washout effects. The final BAU is a competition between the asymmetric decay of right-handed neutrinos (RHNs) and the washout of the existing asymmetry. In this talk, I...
Doubly charged Higgs-like particles (H++ and H--) are predicted in a variety of BSM models which include the Drell-Yan-like production mechanism, q qbar -> Z/gamma* -> H++ H--. Each doubly charged Higgs can decay to a pair of same-sign standard model leptons, producing events with distinctive signatures including electrons, muons, and taus. The most stringent experimental lower bound on the...
