Particle Physics on the Plains​ 2022 Part 2

22 Oct 2022, 08:15 → 23 Oct 2022, 14:00 US/Central

2001 Malott Hall (University of Kansas)

Particle Physics on the Plains will be held on October 22-23, 2022, at the University of Kansas. The workshop facilitates a discussion about the latest results in particle phenomenology and theory among  particle theorists in the region.

The format will be a hybrid.  However, talks will be in person unless an accommodation is made or there are extenuating circumstances.  Accommodations are on a case-by-case basis and can be made by contacting the organizers. 

Talks are intended to be mostly student/postdoc talks.  If there is room in the schedule, we will add faculty talks.  Nevertheless, this is an excellent opportunity for faculty to keep up on research in the region and gather for lengthy discussions.

September 19, 2022  There are funds available to help support lodging for students and postdocs who give talks. To be eligible for these funds students/postdocs must register and submit a talk abstract by 11:59 pm CDT September 19, 2022.  Preference will be given to regional theoretical particle physics students/postdocs.  However, provided funds are available, we will support the lodging of additional students/postdocs.  Further details are on the registration and lodging pages.

September 21, 2022  Deadline for hotel reservation under our group rate at the Baymont.  Information can be found on the lodging page.

October 14, 2022 Registration closes at midnight CDT.

Confirmed invited speaker:  Zhen Liu (University of Minnesota) has agree to attend and give a talk.

Masks are strongly encouraged.  Information about COVID-19 regulations at KU can be found here: https://protect.ku.edu/

 

Lunch on Saturday and coffee breaks will be provided during the conference.

Driving directions on Google maps from the hotel to campus can be found on the lodging page.

This workshop is supported in part by the Research Excellence Initiative of the College of Liberal Arts and Sciences at the University of Kansas, the University of Kansas Office of Research, and the University of Kansas Department of Physics & Astronomy.

Previous year's website:  2017, 2018, 2019, 2022 (Part 1)

Organizers: KC Kong, Ian Lewis (chair), Douglas McKay, John Ralston

Saturday 22 October

08:30 → 09:00 Registration

09:00 → 10:20 Session 1

Convener: Francesc Ferrer (Washington University in St Louis)

09:00 Stellar Binary Hardening from Solar Mass Primordial Black Holes

Light primordial black holes (PBHs) can explain the observed dark matter abundance while being consistent with the current indirect detection constraints. These light PBHs could have a wide range of effects on stellar binaries. In particular, the separation of binary systems may be sensitive to the mass and abundance of PBHs which perturb them. This sensitivity could show up in current and future binary data. The separation distribution of stellar binaries can possibly be used to probe PBHs.

Speaker: Badal Bhalla (University of Oklahoma)

SBH and Light PBHs - Kansas.pdf

09:20 Correlating Gravitational Wave and Gamma-ray Signals from Primordial Black Holes

Asteroid-mass primordial black holes (PBH) can explain the observed dark matter abundance while being consistent with the current indirect detection constraints. These PBH can produce gamma-ray signals from Hawking radiation that are within the sensitivity of future MeV sky searches. PBH which give rise to such observable gamma-ray signals have a cosmic origin from large primordial fluctuations. There must then be a companion, stochastic gravitational wave (GW) background produced by the same curvature fluctuations. We demonstrate that the resulting GW signals will be well within the sensitivity of future GW detectors. The multi-messenger signal from the observed gamma-rays and GW will allow a precise measurement of the primordial curvature perturbation that produces the PBH. We argue that the resulting correlation between the two types of observations can provide a smoking-gun signal of PBH.

Speaker: Tao Xu

TaoXu.pdf

09:40 The Baryon-Dark Matter Coincidence Problem and Primordial Black Holes

We study the Baryon-Dark Matter Coincidence Problem with primordial black holes (PBHs). PBHs induce baryogenesis through the Baumann-Steinhardt-Turok mechanism, by Hawking evaporating into a beyond-Standard Model particle $X$ that has baryon number and CP-violating couplings to the Standard Model. Dark matter is also produced in our mechanism. The gravitational wave signatures are presented, and a UV completion is discussed.

Speaker: Thomas Gehrman (University of Oklahoma)

Conference Presentation.pdf

10:00 Globular-cluster constraints on the axion-photon coupling

We propose a novel way to seek eV-MeV axions in a globular cluster. Axions can be produced inside stars via the Primakoff process and photon coalescence, and subsequently, decay into two photons. In particular, the hot and dense plasma in the core of horizontal branch (HB) stars in globular clusters could produce eV-MeV axion efficiently. Future MeV gamma-ray telescopes might be able to detect photons from the decay of axons produced in those stars.

Speaker: Takuya Okawa

ppppart2_okawa.pdf

10:20 → 10:50 Coffee Break

10:50 → 12:25 Session 2

Convener: Andrew Ivanov (Kansas State University (US))

10:50 Welcome from Department Chair

11:00 Ultrahigh Energy Neutrino Physics and Astrophysics...With Radar!

Speaker: steven prohira (University of Kansas)

11:20 Phenomenology of the Semi-Leptonic Double Higgs Channel

We examine the phenomenology of the double Higgs production at the High-luminosity Large Hadron Collider in a final state with two b-tagged jets, one lepton, and two light jets, (HH -> bbWW*), called the semi-leptonic channel. Historically the significance of this channel has been considered negligible, but we believe it is more optimistic than previously thought. We use a suite of kinematic variables including high-level variables Higgsness and Topness that were originally developed for the di-lepton channel and a neural network to discriminate between our signal and its extremely dominant background process $t\overline{t}$. We also found seven new kinematic variables that show promising discrimination for the semi-leptonic channel and can be easily generalized to the di-leptonic channel. Through this, we improve the signal significance in this decay mode by more than a factor of 3.

Speaker: Curtis Munro Mc Lennan (Kansas State University (US))

Particle_Physics_on_the_plains_presentation.pdf

11:40 NLO Multijet Merging for Higgs Production Beyond the VBF Approximation, Part I

In this talk I will present results of the situation of electroweak Higgs boson production using both the NLO multijet merging and NLO matching frameworks provided by the general purpose event generator Herwig 7. For the simulation of the hard scattering processes, we use the HJets library for the full calculation and VBFNLO for the approximate calculation to compute the 2 -> 2 + n amplitudes at tree-level with n=2,3,4 and at one-loop with n=2,3.

Speaker: Terrance Figy (Wichita State University)

GitHub for Results

ParticlesOnThePlains-Fall2022-TFigy.pdf

ParticlesOnThePlains-Fall2022-TFigy.pptx

12:05 NLO Multijet Merging for Higgs Production Beyond the VBF Approximation, Part II

About ten years ago, the ATLAS and CMS collaborations at the Large Hadron Collider (LHC) announced a landmark discovery in particle physics, the discovery of the Higgs boson predicted by the Standard Model. The Higgs production through vector boson fusion (VBF) process plays a key role in the precision measurements of properties of the Higgs boson. We present an investigation of the NLO multijet merging and matching results that employ the general purpose Monte Carlo event generator Herwig 7. In part I of this talk, Dr. Figy will present the full calculation results using the HJets library for 2-> h+n amplitudes where n=2,3,4 at tree level and n=2,3 at one-loop. The NLO merging predictions are compared to the NLO plus parton shower (NLOPS) predictions. I will perform comparison results of the full calculations and approximate calculations using VBFNLO with different selection criteria. This talk is based on the paper Eur.Phys.J.C 82 (2022) 8, 704.

Speaker: Tinghua Chen (Wichita State University)

TChen_Particle_Physics_on_the_Plains_2022_part2.pdf

12:25 → 14:00 Lunch

14:00 → 15:35 Session 3

Convener: Peisi Huang

14:00 Hunting Gluonic ALPs

Axion coupling to gluons is the defining property that connects it to the Strong CP puzzle. People have recently considered heavier axions, often dubbed Axion-Like-Particles (ALPs), as a generic EFT for pseudo-scalars. However, the effects have mostly been focused on other couplings as they are much easier to calculate and observe. In this talk, I will describe the attempt to consider Strong-CP solving heavy axions that beneficially are more stable potential against Planck suppressed perturbations. The axion mass and potential receive reinforcement from a mirror sector. Then, I will describe a class of searches motivated by this consideration and the generic considerations for gluonic ALPs. The searches for such gluonic heavy axions are challenging due to the typical large QCD background. New search ideas, projections, and results at the LHC, FASER, DUNE, and ArgoNeuT will be presented.

Speakers: Zhen Liu, Zhen Liu, Zhen Liu (University of Minnesota (US))

8_ALP_ZhenLiu_ParticlePhysicsPlains_30mins.pdf

14:35 Probing the Bell's inequalities at the LHC with top-quark pair production

The Large Hadron Collider provides an excellent environment to study the quantum entanglement and Bell's inequality at the highest energy available today. In this presentation, we explore the possible observation of the entanglement in the top quark production, which represents a system of two qubits.

Speaker: Alberto Navarro

PPP_2022_A_Navarro.pdf

14:55 Collider Physics with Symbolic Regression

Symbolic Regression represents a collection of methods to derive the symbolical expression of a formula given numerical values of the variables and the function values. Recent advances in machine learning have improved the performance of symbolic regression, and have attracted attention to use it to solve physics problems. We attempted to use symbolic regression to derive analytical formulas that are needed at various stages of a typical experimental analysis in collider phenomenology. We will demonstrate using two separate applications, that machine learning can derive the analytical expression given the appropriate training data.

Speaker: Zhongtian Dong (University of Kansas)

PPP22.pdf

15:15 New physics searches in top production processes using machine learning

The angular moments for the Z boson can be used as analyzers for the underlying production dynamics for $Z$ associated top pair and single top processes. We show that the angular moments for the $Z$ boson can boost new physics sensitivity in the $t\bar{t}Z$ processes at the high luminosity LHC (HL-LHC), using machine learning techniques. We present the HL-LHC sensitivity to new physics effects parametrized in terms of the Standard Model Effective Field theory framework.

Speaker: Roshan Mammen Abraham

PPP22_RMA.pdf

15:35 → 16:05 Coffee Break

16:05 → 17:25 Session 4

Convener: Dr Bhupal Dev (Washington University in St. Louis)

16:05 Deep learning techniques for Imaging Air Cherenkov Telescopes

Very High Energy (VHE) gamma rays and charged cosmic rays (CCRs) provide a unique observational window into the inner workings of our universe. With the advent of new observatories, they provide access to exotic events and Beyond Standard Model (BSM) phenomena at the center-of-mass energy scale, currently inaccessible to terrestrial experiments like the Large Hadron Collider (LHC). One of the major challenges at Imaging Air Cherenkov telescopes (IACTs) designed to look for VHE gamma rays, is the separation of gamma ray-initiated air showers from the background of air showers triggered by CCRs. Two other less well-studied problems relevant to IACTs are a) the classification of different primary nuclei among the CCR events and b) identification of anomalous events initiated by Beyond Standard Model (BSM) particles that do not conform to known shower patterns of either hadronic or gamma ray primaries. In our work, we have tried to tackle these problems by using machine learning approaches (more specifically, deep learning algorithms). Traditional cosmic ray studies utilize multivariate analysis based on derived shower properties to perform gamma ray-CCR separation. In our work, we are training our ML architectures on full simulated shower images, as opposed to training on just a few derived shower properties in order to avoid the significant reduction of shower information.

In this work, we simulate air shower images initiated by Standard Model (SM) primaries - gamma, proton, Helium and Carbon and employ the techniques of binary and multi-category classification using convolutional neural networks (CNNs). CNN is an Artificial Neural Network that is extremely useful for image recognition and pattern detection. Additionally, by simulating Z$'$ shower images as a prototype exotic event, we pioneer the use of Autoencoder to pick out exotic BSM-initiated showers that are visually indistinguishable from the standard cosmic ray showers. The latter technique has been studied previously in the context of collider physics, to tag anomalous BSM candidates in a model-independent way. In this study, for the first time, we demonstrate the efficacy of these techniques in the domain of VHE gamma ray experiments.

Our binary classifier is capable of distinguishing air showers triggered by gamma rays from the ones initiated by protons with $>$ 99% accuracy. Our multi-category classifier has given good but relatively modest performance for the identification of nuclear species, with best identification of carbon nuclei initiated showers. Proton and helium nuclei-initiated showers are found relatively harder to differentiate. Our autoencoder has also been able to tag Z$'$-initiated shower images as anomalous images with around 99% accuracy. We hope that the techniques used in our work can potentially be implemented in the current and future cosmic ray experiments to maximize the physics potential of these experiments. This would especially enable us to tap into the full potential of cosmic ray experiments as BSM search tools.

Speaker: Ms Writasree Maitra (Department of Physics, Washington University in St. Louis)

DeepLearning_IACT_Writasree.pdf

16:25 New Physics in Meson Decays at Beam Dump and Stopped Pion Facilities

We explain the MiniBooNE low energy excess utilizing three body decays of charged mesons into a lepton, neutrino, and a dark bosonic state, in conjunction with Primakoff-like photoconversion of such states in order to explain the angular spectrum. Thus, dark-sector interpretations can be reinstated as plausible solutions to the excess. We explore a new space of EFTs that fit into this general phenomenological framework and show how complimentary searches can be performed at stopped-pion experiments. We present some preliminary studies on the capabilities of the CCM experiment in this light.

Speaker: Adrian Raphael Thompson

ppotp2022_thompson.pdf

16:45 Inelastic dark matter nucleus scattering in stopped pion experiment

We study inelastic dark matter-nucleus scattering in stopped pion experiments by nuclear shell model. We find that the inelastic scattering is dominated by Gamow-Teller (GT) transition. Nuclear shell model code, BIGSTICK, calculates GT transitions and the deexcitation photons for the nuclei such as Na23, Ar40, and I127. Given the experiment setup (COHERENT for example) we can estimate event rate of the scattering. Therefore we can probe new regions of DM parameter space with the photon spectrum.

Speaker: Wei-Chih Huang

Plains_ 2022.pdf

17:05 Correlating the Magnetic Moments of Neutrinos and Charged Leptons

In this talk, I shall describe how the neutrino transition magnetic moment and charged lepton magnetic moments are correlated in various classes of models. In particular, I will consider two different models. One is based on an approximate $SU(2)_H$ symmetry, and the other is based on the spin symmetry mechanism: both these models can generate a large neutrino magnetic moment without inducing unacceptably large neutrino masses.

Speaker: vishnupk Padmanabhan Kovilakam

gm2_NMM_Updated_PPP_2022.pdf

Sunday 23 October

08:30 → 09:00 Coffee

09:00 → 10:45 Session 5

Convener: Kuver Sinha (University of Oklahoma)

09:00 Connecting Cabibbo Angle Anomaly and CDF W mass

High precision determinations of $V_{ud}$ and $V_{us}$ indicate a $\sim4\sigma$ deficit in the first-row unitarity of the CKM matrix, commonly referred to as the Cabibbo Angle Anomaly (CAA). We explore a vector-like quark solution to the anomaly in a UV-complete left-right symmetric model, in correlation with the recent $W$-boson mass shift reported by the CDF collaboration.

Speaker: Ritu Dcruz (Oklahoma State University)

Cabibbo anomaly and CDF W in LRSM.pdf

09:20 E6 Models in Light of Precision MW Measurements

We propose a solution to the recent W mass measurement by embedding the Standard Model within $E_6$ models. The presence of a new U(1) group shifts the W boson mass at the tree level and introduces a new gauge boson $Z′$ which has been searched for at collider experiments. In this article, we identity the parameter space that explains the new $W$ mass measurement and is consistent with current experimental $Z′$ searches. As U(1) extensions can be accommodated in supersymmetric models, we also consider the supersymmetric scenario of $E_6$ models, and show that a 125 GeV Higgs may be easily achieved in such settings.

Speaker: Cash Hauptmann

E_6 Models in Light of Precision M_W.pdf

09:40 Leptoquark-vectorlike quark model for the CDF $m_{W}$ , $(g − 2)_{\mu}$, $R_{K^{(\ast)}}$ anomalies and neutrino mass

Recently, the CDF collaboration has reported a substantial $7\sigma$ deviation of the W-boson mass from the Standard Model (SM) prediction. Furthermore, the Muon g-2 Experiment recently confirmed the longstanding tension in $(g −2)_{\mu}$. Besides, the updated result from the LHCb collaboration found evidence for the breaking of lepton universality in beauty-quark decays, which shows a $3.1\sigma$ discrepancy and is consistent with their previous measurements. Motivated by several of these drawbacks of the SM, in this work, we propose a model consisting of two scalar leptoquarks and a vectorlike quark to simultaneously address the W-boson mass shift, the $(g −2)_{\mu}$, and anomalies in the neutral current transitions of the B-meson decays. The proposed model also sheds light on the origin of neutrino mass and can be fully tested at the future colliders.

Speaker: Talal Ahmed Chowdhury

Talal_Chowdhury.pdf

10:05 First Order Electroweak Phase Transitions in the Standard Model with a Singlet Extension

A common assumption about the early universe is that it underwent an electroweak phase transition (EWPT). Though the standard model (SM) is able to restore the electroweak symmetry through a smooth cross over PT, we require a strongly first-order PT to ensure electroweak baryogenesis, requiring us to look at new physics beyond the SM. The simplest case to extend the SM is to add a real singlet field, which allows for a first-order EWPTs (FOEPT) to occur.

Starting with the most general higgs+singlet Lagrangian, we fixed four of its coupling constants as functions of the three quartics, the singlet and higg’s mass and vacuum expectation value, whose range of values had more experimental motivation than the former. We scanned over these five free parameters, requiring each point to be a FOEPT and the singlet mass to be between zero and twice the Higgs mass. The resulting parameter space was studied for light and intermediate singlet masses less than half the higgs mass and masses above this, respectively. In each region we explored the main modes of production, looking for complimentary modes in the parameter space to aid in di-Higgs precision measurements.

Speaker: Anthony Hooper

FOEPT_in_the_SM_with_a_Singlet_Extension__Particle_Physics_on_the_Plains_2022___Part_Two.pdf

(handout)FOEPT_in_the_SM_with_a_Singlet_Extension__Particle_Physics_on_the_Plains_2022___Part_Two.pdf

10:25 Resonant top pair searches at the LHC: a window to electroweak phase transition

The dynamics of electroweak phase transition could have profound consequences for particle physics and cosmology. We study the prospects for the HL-LHC to probe the strong first-order electroweak phase transition (SFOEWPT) regime in the 2HDM. We focus on the Higgstrahlung channel $pp\to ZH/A$ with a resonant top-quark pair final state $H/A\to t\bar t$. We find that the top-quark pair final state renders the largest sensitivity to the SFOEWPT regime compared to the other Higgstrahlung searches already performed by ATLAS and CMS, that focus on the $H/A\to bb$ and $H\to WW$ final states. We also derive the complementarity of the Higgstrahlung searches with other relevant classes of searches at the HL-LHC and compare them with the gravitational wave sensitivity at LISA.

Speaker: AJAY Kaladharan

EWPT_ZH_PPP.pdf

10:45 → 11:15 Coffee Break

11:15 → 13:05 Session 6

Convener: Dorival Goncalves

11:15 Phenomenology of Two Higgs Doublet Model with Complex Scalar Singlet extension

Extension of the Two Higgs Doublet model augmented with a complex scalar singlet (2HDMS) is a well motivated candidate for Beyond Standard Model (BSM) Physics. In this talk, we focus on different aspects of 2HDMS including dark matter (DM) phenomenology of 2HDMS and the impact of inflation on low energy phenomenology. We have performed parameter scans to study the impact of relic density and direct detection scenarios on the model parameter space for both cases. Some representative benchmarks are chosen and potential signals at future e+e- colliders are presented.

Speaker: Juhi Dutta

JuhiDutta_Kansas2.pdf

11:35 CP Violating Top Yukawa at the Future Muon Collider

The project studies a CP-violating top Yukawa coupling at a future muon collider. The signal processes include $tth$, $tth\nu\nu$, and $tbh\mu\nu$ decaying semi-leptonically. Using energies of 1, 3, 10, and 30 TeV, we show cross section dependence on the CP phase and will discuss how different signals dominate at different benchmark energies. Projected bounds on $\alpha$ at 95% CL are presented given the Standard Model case, and we show luminosity required for $5\sigma$ discovery and $2\sigma$ exclusion for different CP phases.

Speaker: Morgan Cassidy

11:55 Probes of new physics in final states with two taus and two muons

The recent experimental results of muon $g-2$ from the Fermilab and the longstanding discrepancies of lepton flavor universality violation in rare decays of $B$-mesons could be strong hints of new physics beyond the Standard Model. We had earlier shown that under a minimal $R$-parity violating supersymmetric scenario with relatively light third-generation sfermions (called 'RPV3'), the sneutrino gives the main contribution to muon $g-2$ anomaly. Here we propose a scenario in the sneutrino parameter space that leads to a distinct collider signal $\tau^+ \tau^- \mu^+ \mu^-$ from the sneutrino pair production. We further analyze this signal using the data recorded during Run-2 of the LHC and show the discovery prospect of this scenario.

Speaker: Fang Xu

PPP2022_Part2 - Fang Xu.pdf

12:15 Lepton Number Violation at the LHC

Existing searches for lepton number violation (LNV) suggest that lepton number is an approximate symmetry of nature. The LHC can provide a probe of $L$ violation that is complementary to low-energy experiments. In this talk, we examine collider signatures of LNV. Using some illustrative models, we emphasize that a collider signature of $L$ violation requires the existence of an observable non-zero lepton number in the final state.

Speaker: Rahool Kumar Barman (Oklahoma State University)

PPP-part2-Talk.pdf

12:35 Scalar decays in Type II seesaw model

In the type II seesaw model, there are seven physical Higgs states in mass basis and those can be categorized as charged Higgs bosons ($H^±$, $H^{±±}$) and the neutral Higgs bosons ($A^0$, $H^0$,$h^0$). At LHC, one of the primary ways to search for Higgs is via its decay to two photons. We studied the two-photon decay channel of SM-like component ($H^0$) of CP-even Higgs bosons and the pseudo scalar ($A^0$) in CP-odd bosons. For these loop-induced processes, we used computer-algebraic methods to generate Feynman diagrams and to obtain analytic expressions for $Γ(H^0→γγ)$ and $Γ(A^0→γγ)$. Some numerical results given by the analytic expression under the potential stability bounds condition for the $H^0→γγ$ process were compared with the SM.

Speaker: Mr Bathiya Samarakoon (Wichita State University)

Type2seesaw_model.pdf

12:55 Closing Remarks