Particle Physics on the Plains​ 2018

13 Oct 2018, 08:30 → 14 Oct 2018, 23:10 US/Central

1160 Integrated Science Building (University of Kansas)

Ian Lewis (The University of Kansas)

Particle Physics on the Plains will be held on October 13-14, 2018, 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.

September 9, 2018  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, submit a talk abstract, and indicate a preferred roommate by 5:00 pm CDT September 9, 2018.  Further details are on the registration and accommodation pages.

September 12, 2018  Deadline for hotel reservation under our group rate.  Information can be found on the accommodation page.

September 28, 2018 Registration closes at 5:00 pm CDT.

Lunch on Saturday, coffee breaks, and a simple breakfast will be provided for during the workshop.

Invited Keynote Speaker: Prof. Carlos Wagner (Univ. of Chicago/Argonne National Laboratory)

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

Previous year's website:  2017

Saturday 13 October

08:30 → 09:00 Registration/Breakfast

09:00 → 10:45 Higgs Physics I

Convener: Kuver Sinha (University of Oklahoma)

09:00 Welcome

Speakers: Hume Feldman (University of Kansas), Ian Lewis (The University of Kansas)

Welcome.pdf

09:15 Experimental Results for BSM at the LHC

Speaker: Christopher Rogan (The University of Kansas (US))

Rogan_PPP_13_10_18.pdf

09:45 Contribution of Scalar Singlet and Higher Dimension Operator in Higgs Physics

Standard model is successful in explaining Higgs physics, however new physics beyond the standard model may yet be expected. We study how the inclusion of real singlet scalar and dimension 5 operators effect SM Higgs physics. We do this by studying the deviations of the total width and branching ratios of the Higgs from the SM predictions. We also study the limit on scalar mixing angle and Wilson coefficients by a fit to the combined ATLAS/CMS gluon fusion signal strength for the Higgs production as well as by a fit to the combined ATLAS/CMS signal strengths for the different Higgs decay channels.

Speaker: Shekhar Adhikari

pp_plains.pdf

10:05 Interference Effect in Di-Higgs Production in SUSY models (MSSM with Gauge Extensions)

It has been shown that the di-Higgs production cross section could be enhanced by resonant processes or non-resonant processes related to physics beyond the Standard Model. Nonetheless, no study has been done on the interference effect of resonant and non-resonant di-Higgs production (within the context of Minimal Supersymmetric Standard Model). In this talk, I would like to discuss the consequence of interference between resonant and nonresonant di-Higgs production in the MSSM (with an additional SU(2) gauge group). The SM-like Higgs mass can be around 125 GeV by introducing an additional SU(2) gauge group, which modifies the trilinear coupling and therefore modifies the non-resonant production. The nonresonant production is also modified through the modification of the top couplings. Then in certain region of the parameter space the interference between the non-resonant production and the resonant production through the heavy CP-even Higgs is important. I am going to show the relevant parameter space and show the interference effect in those regions. ( The model under consideration allows a large region of parameter space where the mass of light CP-even neutral Higgs is around 125 GeV, and constraints from electroweak precision data are satisfied.)

Speaker: Yu Hang Ng (University of Nebraska-Lincoln)

Kansas Workshop.pdf

Kansas Workshop.ppt

Kansas Workshop_v2.pdf

Kansas Workshop_v2.ppt

10:25 Resonant Di-Higgs Production at Gravitational Wave Benchmarks: A Collider Study using Machine Learning

I will talk about our recent work on a new study of the resonant di-Higgs production using machine-learning techniques for collider analysis and
focusing on benchmarks which can generate detectable gravitational wave signals from electroweak phase transition at space-based interferometer gravitational wave detectors.(paper link https://arxiv.org/abs/1808.08974)

Speaker: Huaike Guo (Institute of Theoretical Physics, Chinese Academy of Sciences)

Huaike.pdf

10:45 → 11:15 Coffee Break

11:15 → 12:20 Higgs Physics II

Convener: Kaladi Babu (Oklahoma State University)

11:15 Multistep Single-Field Strong Phase Transitions from New TeV Scale Fermions

In spite of the vast literature on the subject of strongly first order Electroweak Phase Transitions (SFOEWPT), which can provide the necessary conditions for generating the Baryon Asymmetry in the Universe, fermion-induced SFOEWPTs still remain a rather uncharted territory. In this talk, we consider a simple fermionic extension of the Standard Model (SM) involving one $SU(2)_L$ doublet and two singlet Vector-Like Leptons (VLLs), strongly coupled to the Higgs scalar and with masses close to the TeV scale. We show how such a simple scenario can give rise to a non-trivial thermal history of the Universe, involving strongly first order multistep phase transitions occurring at temperatures close to the electroweak (EW) scale. Finally, we investigate the distinct Gravitational Wave (GW) signatures of these phase transitions at future GW detectors, such as eLISA, and briefly discuss how the VLLs can be searched for at the LHC.

Speaker: Andrei Angelescu (University of Nebraska-Lincoln)

angelescu_plains2018.pdf

11:35 A Comparative Study of Electroweak Higgs Boson Production at Future Hadron Colliders

The discovery of the Higgs boson has opened the door to the next phase of exploration in particle physics. Since the Higgs boson was found in July 2012 at CERN's Large Hadron Collider (LHC), many researches and experiments tried to measure its properties, making processes involving Higgs production interesting and important in many different ways.

By using a Monte Carlo event generator named Herwig 7, Higgs plus two jet production processes have been simulated with two different matrix elements, HJets++ and VBFNLO. Higgs plus two jet production was analyzed at 14 TeV, 33 TeV, and 100 TeV. Presented here are the differential cross section at the leading order and next-to-leading order with matched parton showers.

Speaker: Tinghua Chen (Wichita State University)

TChen-Talk.pdf

11:55 A Forward Branching Phase Space Generator for Hadron Colliders

In this talk I will present a projective phase space generator appropriate for hadron collider geometry. The generator integrates over bremsstrahlung events which project back to a single, fixed Born event. The projection is dictated by the experimental jet algorithm allowing for the forward branching phase space generator to integrate out the jet masses and initial state radiation. When integrating over the virtual and bremsstrahlung amplitudes this results in a single K-factor, assigning an event probability to each Born event. This K-factor is calculable as a perturbative expansion in the strong coupling constant. One can build observables from the Born kinematics, giving identical results to traditional observables as long as the observable does not depend on the infrared sensitive jet mass or initial state radiation. See article on Inspire

Speaker: Terrance Figy (Wichita State University)

ParticlePhysicsOnThePlains_TMFigy_2018.pdf

12:20 → 14:00 Lunch-Boxed Lunches are Provided

14:00 → 15:20 Beyond the Standard Model I

14:00 Partial Compositeness and The Fermion/Sfermion Mass Hierarchy

The fermion mass hierarchy does not have an explanation in the Standard Model (SM). Moreover, an inverted hierarchy of the sfermion masses is suggested by the constraints from LHC data. To explain these known and expected hierarchies, we consider a supersymmetric model that uses partial-compositeness. The Higgs and third-generation matter superfields are elementary while the first two matter generations are composite with supersymmetry assumed to be broken by the strong dynamics. Linear mixing between elementary superfields and supersymmetric composite operators with large anomalous dimensions is responsible for simultaneously generating the fermion and sfermion mass hierarchies. This partial-compositeness framework can be considered to be dual by the AdS/CFT correspondence to the idea of a warped extra dimension that explains the mass hierarchies by wavefunction overlap.

Speaker: Yusuf Buyukdag (University of Minnesota, Twin Cities)

Yusuf Buyukdag-ParticlePhysicsonthePlains2018.pdf

14:20 Split-Supersymmetry in AdS$_5$

Supersymmetric models are subject both to direct constraints from collider searches and to indirect limits from electroweak observables such as the Higgs mass and flavor-changing processes. A minimal scenario consistent with current experimental data suggests a supersymmetric spectrum with a split sfermion sector. Such a spectrum can naturally be realized when supersymmetry is broken in a warped geometry where the sfermion spectrum is related to the Standard Model fermion mass spectrum. We present a supersymmetric model constructed in AdS$_5$ compactified over an orbifold that predicts a sfermion mass hierarchy that inverts the ordering of fermion mass hierarchy. Gauginos and Higgsinos are typically several TeV, while the third-generation sfermions are $\mathcal{O}(10)$ TeV, consistent with the observed 125 GeV Higgs mass. The first- and second-generation sfermions are above 100 TeV, ameliorating the flavor problem. The gravitino, in the keV to TeV mass range, is the LSP, providing a warm dark matter candidate. We explore the rich parameter space of the model and discuss the details of two benchmark sparticle spectra and their calculation.

Speaker: Andrew Miller (University of Minnesota)

AndrewMiller-Plains2018.pdf

14:40 Dark Energy Constraints from Expansion Rate and Density Fluctuation Data

We present best-fit constraints on three different dark energy models. We analyzed 31 measurements of the Hubble expansion rate, as well as 11 distance measurements scaled to the sound horizon set by baryon acoustic oscillations. Our analysis finds that the data favor a slightly closed Lambda-CDM model (as opposed to the conventional flat Lambda-CDM model), although not above the 1-sigma level.

Speaker: Joseph Ryan (Kansas State University)

Dark Energy Constraints.pdf

Dark Energy Constraints.pptx

15:00 Lepton flavor violation induced by a neutral scalar at future lepton colliders

Many new physics scenarios beyond the Standard Model often necessitate the existence of a (light) neutral scalar H, which might couple to the charged leptons in a flavor violating way, while evading all existing constraints. Such scalars could be effectively produced at future lepton colliders like CEPC, ILC, FCC-ee and CLIC, either on-shell or off-shell, and induce lepton flavor violating (LFV) signals. We find that a large parameter space of the scalar mass and the LFV couplings can be probed, well beyond the current low-energy constraints in the lepton sector. The neutral scalar explanation of the muon g-2 anomaly could also be directly tested at these colliders.

Speaker: Dr Yongchao Zhang

LFV_PPP2018.pdf

15:20 → 15:50 Coffee Break

15:50 → 17:25 LHC Phenomenology I

Convener: Peisi Huang (University of Nebraska-Lincoln)

15:50 Flavor Changing Heavy Higgs Interactions with Leptons at Hadron Colliders

We adopt a general two Higgs doublet model (2HDM) to study the signature
of flavor changing neutral Higgs (FCNH) decays into leptons at the CERN
Large Hadron Collider (LHC) as well as future hadron colliders
$pp \to \phi^0 \to \tau^\mp\mu^\pm +X$, where $\phi^0$ could be
a CP-even scalar [$h^0$ (lighter), $H^0$ (heavier)]
or a CP-odd pseudoscalar ($A^0$).
%
The LHC measurements of the light Higgs boson ($h^0$) favor
the alignment limit of a 2HDM, in which the couplings of $h^0$
approach Standard Model values.
In this limit, FCNH couplings of the light Higgs boson $h^0$ are
naturally suppressed by a small mixing parameter $\cos(\beta-\alpha)$,
while the FCNH couplings of heavier neutral Higgs bosons $H^0, A^0$
are sustained by $\sin(\beta-\alpha) \sim 1$.
%
We evaluate the production rate of physics background from dominant processes
($\tau^+\tau^-, WW, ZZ, Wq, Wg, t\bar{t}$) with realistic acceptance
cuts and tagging efficiencies. Promising results are found for the LHC
collision energies $\sqrt{s} = 13$ TeV and 14 TeV.
%
In addition, we study the discovery poential of future pp colliders
with $\sqrt{s} = 27$ TeV and 100 TeV.

Speaker: Mr Rishabh Jain (University of Oklahoma)

Rishabh_KU_2018.pdf

16:10 Hunting for Maverick Top Partners

Most searches for vector-like top partners (T) are concerned with the pair and single productions, strictly focusing on three conventional T decays (i.e. t Z, t h and Wb). As bounds become increasingly stringent, however, the LHC energy will be saturated and the utility of these channels greatly diminish.

This takes forward our task to scrutinize every corner of a parameter space, including the region where a mixing angle between T and the SM top quark is negligibly small. It opens a new avenue to search for T of which the decay pattern can be significantly altered with new decay modes. In a model where the SM is extended by an SU(2) singlet T and a gauge singlet scalar (S), it is possible that S can mediate not only loop-induced single T productions in association with a top quark (i.e. T + top), but also new decays of T (i.e. top + gluon, top + photon, and top + S).

We also present dedicated collider analysis for the HL-LHC, and estimate a sensitivity reach of this new channel using a jet-substructure method.

Reference: arXiv:1803.06351

Speaker: Jeong Han Kim (University of Kansas)

Ian_2018_Han.pdf

16:30 Shedding Light on Top Partner at the LHC

We study the radiative decay modes of a TeV scale top partner that decays to SM top plus either photon or gluon. Such decay modes can be dominant especially in the case where the mixing between the top partner and the SM top goes to zero. The top partner is introduced as a color triplet and electroweak singlet. We take a model-independent approach by introducing an effective dimension-five operator to describe the interaction between the top partner and the SM top. We study the pair production of the top partner and investigate its signal sensitivity in the semileptonic channel at the LHC. We use top tagging technique to identify heavy objects and reduce the background. We then present our results in terms of luminosity curves and branching ratio by changing the top partner mass.

Speaker: Haider Alhazmi

Haider_PPP2018.pdf

16:50 GeV scale messengers of Planck Scale Dark Matter.

Speaker: Gopolang Mohlabeng (Brookhaven National Laboratory)

PSDM_KU.pdf

Sunday 14 October

08:30 → 09:00 Breakfast

09:00 → 10:35 Neutrinos and Dark Matter

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

09:00 An R-parity Violating Supersymmetric Explanation of the EeV Events at ANITA

The ANITA balloon experiment has observed two EeV-level, upgoing cascade events, which cannot be explained by the Standard Model neutrino interactions that make the Earth opaque to EeV neutrinos. In this paper, we analyze a long-lived bino interpretation in leptonic R-parity violating supersymmetry. In particular, a TeV-scale bino can be resonantly produced through the interaction of the EeV neutrino with electrons inside Earth and propagate through Earth matter before decaying back to leptons and neutrino near ANITA. For appropriate decay length of the bino, this also explains why IceCube has not seen these events in spite of a higher exposure time. The corresponding RPV coupling required to fit the ANITA data is consistent with the current laboratory bounds. Finally, we find that an isotropic GZK neutrino flux is too small to account for the ANITA events and a non-isotropic EeV neutrino flux, presumably coming from point sources, such as GRB or blazars, is needed.

Speaker: Yicong Sui (Washington University in Saint Louis)

PPT_for_PPP_YicongSui.pdf

09:20 Leptogenesis and neutrino mass generation in LR symmetric model

Speaker: Anil Thapa

Anil_Plains_Lepto.pdf

09:40 Galactic Dark Matter Population as the Source of Neutrino Masses

The extremely small but non-zero neutrino masses has no explanation in the Standard Model. We propose a new mechanism for neutrino mass generation, unrelated to the Higgs mechanism, in which neutrinos get their mass via long range interactions with dark matter. Our model predicts a location dependent neutrino mass and also implies that relic neutrinos are not present in galaxies due to having been repelled by the dark matter.

Speaker: Matthew Sullivan (University of Kansas)

Matthew Sullivan.pdf

10:00 Reflections On Supersymmetry Searches at the LHC

Speaker: Carlos E.M. Wagner (University of Chicago)

Wagner-Kansas.10.18.pdf

10:35 → 11:05 Coffee Break

11:05 → 12:45 Beyond the Standard Model II

Convener: John Ralston (University of Kansas)

11:05 Anomalous coupling studies with intact protons at the LHC

We will describe the sensitivities to quartic photon anomalous couplings at the LHC in the diphoton, photon+Z, WW channels at the LHC leading to unprecedented sensitivities. We will also describe the sensitivities to axion-like particles at high mass at the LHC in the same channel.

Speaker: Justin Andrew Williams (The University of Kansas (US))

jwilliams_aqgc.pdf

11:25 Two Higgs Doublet Model with New Mass Matrix Ansatz

We show that within the two Higgs doublet model (T2HDM), where both Higgs doublet couple to fermions in a same hierarchical pattern, there can be significant deviations in the Higgs-fermion couplings with respect to their respective standard model values, consistent with flavor constraints and known properties of the Higgs boson. The model is very predictive, implying unavoidable new physics signals like di-boson resonances (hh and Zh) from novel decays of CP− even and CP− odd Higgs fields at the Large Hadron Collider (LHC) and that may lead to an explanation of some intriguing di-boson signatures.

Speaker: SUDIP JANA (OKLAHOMA STATE UNIVERSITY)

PPP_2018.pdf

PPP_2018.pptx

11:45 Perturbativity constraints on gauge couplings in U(1) extended SM and Left-Right models

To accommodate new physics like the tiny neutrino masses and dark matter, the standard model gauge group can be extended by an extra U(1) or by constructing left-right symmetric models at higher energies. However, the gauge couplings in these beyond the standard model gauge groups can not be arbitrarily large and/or small. Assuming the new physics emerges at the few-TeV scale and requiring the couplings to be perturbative up to the GUT/Planck scale, we examine the lower and upper bounds on the beyond standard model gauge couplings in the U(1) and left-right models, and the implications for the searches of corresponding gauge bosons at current and future high-energy colliders.

Speaker: Garv Chauhan (Washington University in St. Louis)

ParticlePlains_14_OCT_18.pdf

12:05 Gravity safe, electroweak natural axionic solution to strong CP and SUSY $\mu$ problems

Particle physics models with Peccei-Quinn (PQ) symmetry breaking as a consequence of supersymmetry (SUSY) breaking are attractive in that they solve the strong CP problem with a SUSY DFSZ-like axion, link the SUSY breaking and PQ breaking intermediate mass scales and can resolve the SUSY µ problem with a naturalness-required weak scale µ term whilst soft SUSY breaking terms inhabit the multi-TeV regime as required by LHC sparticle mass limits and the Higgs mass measurement. On the negative ledger, models based on global symmetries suffer a generic gravity spoliation problem. We present two models based on the discrete R-symmetry $Z^R_{24}$– which may emerge from compactification of 10-d Lorentzian spacetime in string theory– where the µ term and dangerous proton decay and R-parity violating operators are either suppressed or forbidden while a gravity-safe PQ symmetry emerges as an accidental approximate global symmetry leading to a solution to the strong CP problem and a weak-scale/natural value for the µ term.

Speaker: Dibyashree Sengupta (University of Oklahoma)

Gravity_safe_pq.pdf

12:25 A Mechanism for Community-Wide Determination of the Fundamental Physical Constants of QED and the Standard Model

The values of fundamental physical constants are crucial for testing current theories and their possible extensions. It is not widely appreciated that determining the constants is quite sensitive to how data and theory are selected, and how theoretical and experimental uncertainties are treated. There exists no universal definition of the “best” procedures or constants. Procedures dedicated to finding constants with the highest possible precision generally select data that confirms the theory. Contrary to perceptions, the theory is not tested at the same level as the uncertainties of fitted parameters. The uncertainties found under a given procedure also cannot reliably constrain parameter variations from different procedures. Determining physical constants cannot consistently be done piecemeal, but needs global fits incorporating the shifting relationships between theory and data. We claim it is scientifically productive to include generic alternatives in global fits, if only to test sensitivity to their effects. Since all the constants are coupled, it is generally necessary to re-do global fits to place self-consistent limits on alternative theory parameters, or make discovery claims. Yet the procedural universe where QED and Standard Model theory are defined to be “exact” permits no alternatives. We propose a new mechanism where dependence on data selection, theory, and procedural decision can be explored community-wide. We constructed Constant Finder (http://www.constantfinder.org), a comprehensive automated code and user interface available to anyone via the website with the same name. The site allows users to make their own procedural decisions, adjust experimental and theoretical values and uncertainties, and pose alternatives to theory within several global data-fitting frameworks. Anyone interested can determine the fundamental constants on the basis of data, uncertainties, and theory inputs of their choosing.

Speaker: John Martens (University of Kansas)

plains_constants_2.pdf

12:45 → 12:55 Closing Remarks

Speaker: John Ralston (University of Kansas)

Presentation%207.pdf