KEK Theory Meeting on Particle Physics Phenomenology (KEK-PH2018)

13 Feb 2018, 08:00 → 16 Feb 2018, 18:00 Asia/Tokyo

Building 3 1F, Seminar Hall (KEK)

The annual Theory Meeting on Particle Physics Phenomenology (KEK-­PH2018) will be held at KEK between February 13 - 16, 2018.

This meeting covers many topics in particle physics phenomenology, from the Standard Model and models beyond the Standard Model to particle cosmology and astrophysics. We aim to discuss recent developments in particle physics theories and learn about the latest results and status of various ongoing and planned experiments.

Meeting program includes talks by invited speakers and short talks (about 20 min) by participants. All the talks will be given in English. We aim to provide an opportunity, not only for experts but also for master/Ph.D course students, to learn recent developments in particle physics phenomenology and to activate intensive discussions. The participants will also have the opportunity to present their work through poster presentations.

There will be a Joint Session on the First day (after Lunch session) with another workshop at KEK -  "Workshop on hadronic vacuum polarization contributions to muon g-2".  

 

Late registration is available with no financial and visa support.

 

 Invited Speakers:

==Theory==

• Christoph Bobeth (TUM)       
• Clifford Cheung (Caltech)   
• Kiwoon Choi (IBS)
• Sacha Davidson (Lyon)
• Hooman Davoudiasl (BNL)
• Tony Gherghetta (University of Minnesota)
• Alejandro Ibarra (TUM)
• Michelangelo Mangano (CERN)
• Kentarou Mawatari (Osaka University) 
• Tom Melia (Kavli IPMU)
• Ian Moult (LBNL)
• Yuji Omura (Nagoya University)
• Matt Reece (Harvard University)
• Alessandro Strumia (Pisa University & INFN & CERN)
• Fuminobu Takahashi (Tohoku University)
• Taizan Watari (Kavli IPMU)

==Expt==

• Sudeshna Ganguly  (University of Illinois at Urbana-Champaign)
• Konosuke Iwamoto (University of Tokyo)
• Christopher Neu (University of Virginia)
• Arturo Sanchez Pineda (Universita di Udine, ICTP and CERN )
• Federico Sforza (Tufts University), 
• Phillip Urquijo (University of Melbourne) 
• Takayuki Yamazaki (KEK)
• Ning Zhou (Shanghai Jiau Tong University)

 

Organizers:

Amit Chakraborty,  Motoi Endo,  Toru Goto, Ryuichiro Kitano, Masafumi Kurachi, Sung Hak Lim, Hiroki Matsui, Satoshi Mishima, Shingo Mori, Ryuji Motono, Mihoko Nojiri, Daisuke Nomura, Yutaka Sakamura, Takahiro Terada, Daiki Ueda.

The KEK­PH2018 workshop is supported by SOKENDAI (The Graduate University for Advanced Studies).

Tuesday, 13 February

09:00 → 09:30 Registration

09:30 → 10:30 Talks

Convener: Mihoko Nojiri (KEK)

09:30 Late-time magnetogenesis

I discuss a late-time magnetogenesis scenario, which takes place after the epoch of electron/positron annihilation. It involves an ultralight axion-like particle, constituting the dark matter of the Universe, and a dark U(1) gauge boson introduced to bypass the obstacle from the relatively high conductivity of the cosmic plasma.

Speaker: Kiwoon Choi (CTPU, IBS)

Slides 01_01_KiwoonChoi.pdf

10:00 Lovely phase space

I’ll describe a parameterisation of phase space where the physical (on-shell & momentum conserving) manifold, upon which observables have support, is identified with a coset space for the breaking of a particle number symmetry. I’ll talk about its applications to monte carlo simulation and partial wave analyses.

Speaker: Tom Melia (Kavli IPMU)

Slides 01_02_TomMelia.pdf

10:30 → 11:00 Tea Time

11:00 → 12:00 Talks

Convener: Alejandro Ibarra (Technical University of Munich)

11:00 Axion coupled to hidden sector

The QCD axion may be coupled to a hidden sector. As an example, I will discuss two scenarios in which the QCD axion is coupled to a hidden photon. In the first case, the axion is coupled to massless hidden photons, and such a coupling is known to induce tachyonic instabilities if the coupling is sufficiently strong. I will explain how the tachyonic preheating affects the final axion abundance based on the lattice simulations. In the second case, the axion is coupled to hidden photons in the presence of hidden monopoles. In this case the axion acquires an extra mass due to the Witten effect, which suppresses the final axion abundance.

Speaker: Fuminobu Takahashi (Tohoku University)

Slides Takahashi0213.pdf

11:30 Multi-Messenger Astrophysics in the Gravitational Wave Era

Speaker: Kunihito Ioka (YITP, Kyoto University)

Slides KEKPH_Ioka18_2.pdf

12:00 → 13:30 Lunch

13:30 → 15:30 Joint Session with Muon g-2 Workshop

Convener: Bradley Lee Roberts (Boston University)

13:30 Belle II overview

Speaker: Phillip Urquijo (University of Melbourne)

14:00 Fermilab muon g-2 experiment

Speaker: Sudeshna Ganguly (University of Illinois at Urbana-Champaign)

Slides https://www.dropbox.com/s/lpyvca0kv5vz8ax/HVP_sudeshna.pptx?dl=0

14:30 J-PARC muon g-2 experiment

Speaker: Takayuki Yamazaki (KEK)

Slides 01_07_TakayukiYamazaki.pdf

15:00 New Physics and the Muon g-2

The ~3.5-sigma discrepancy between the measured value of the muon g-2 and the Standard Model prediction could be a signal of new physics. Possible resolutions, originating at both high and low energies, and their phenomenology are discussed.

Speaker: Hooman Davoudiasl (Brookhaven National Laboratory)

Slides 01_08_HoomanDavoudiasl.pdf

15:30 → 15:50 Tea Time

15:50 → 17:30 Short Talks

Convener: Fuminobu Takahashi (Tohoku University)

15:50 High-energy neutrinos from multi-body decaying dark matter

Since the report of the PeV-TeV neutrinos by the IceCube Collaboration, various particle physics models have been proposed to explain the neutrino spectrum by dark matter particles decaying into neutrinos and other Standard Model particles. In such scenarios, simultaneous gamma-ray emission is commonly expected. Therefore, multi-messenger connections are generally important for the indirect searches of dark matters. The recent development of gamma-ray astronomy puts stringent constraints on the properties of dark matter, especially by observations with the Fermi gamma-ray satellite in the last several years. Motivated by the lack of gamma-ray as well as the shape of the neutrino spectrum observed by IceCube, we discuss a scenario in which the DM is a PeV scale particle which couples strongly to other invisible particles and its decay products do not contain a charged particle. As an example to realize such possibilities, we consider a model of fermionic dark matter that decays into a neutrino and many invisible fermions. The dark matter decay is secluded in the sense that the emitted products are mostly neutrinos and dark fermions. One remarkable feature of this model is the resulting broadband neutrino spectra around the energy scale of the dark matter. We apply this model to multi-PeV dark matter, and discuss possible observable consequences in light of the IceCube data. In particular, this model could account for the large flux at medium energies of 10 to 100 TeV, possibly as well as the second peak at PeV, without violating the stringent gamma-ray constraints from Fermi and air-shower experiments such as CASA-MIA.

Speaker: Nagisa Hiroshima (KEK, ICRR)

Slides KEK-ph2018hiroshima.pdf

16:10 Search for New physics with High multiplicity from High energy cosmic rays

We explore the detectability of generic new physics process with high-multiplicity from Ultra-High energy (UHE) neutrinos (above 100 PeV) with the nucleon in the Earth atmosphere. The current sensitivity from the large area air-shower ground detector arrays (Pierre-Auger and TA) are still above various astrophysical models of Cosmic Rays and GZK neutrino flux with large uncertainties. We consider the criterions for the trigger about neutrino-induced new physics air-showers and heavy-nuclei-like features for proton-induced new physics air-showers. We discuss the current bounds on O(10) TeV scale new physics and also the future prospects. Possible new physics interpretations of recent muon excess in highly-inclined air-showers at Pierre Auger and TA is also discussed.

Speaker: Yongsoo Jho (Yonsei University)

Slides KEK-PH2018_20180205_YSJ_.pdf

16:30 Thermal Gravitational Contribution to Dark Matter Production

This talk will be based on 1708.05138 and 1604.04701, We investigate the particle production from thermal gravitational annihilation in the very early universe, which is an important contribution for particles that might not be in thermal equilibrium or/and might only have gravitational interaction, such as dark matter. We give the relevant analytical formulas for spin 0, 1/2 and 1 particles and discuss some effects from inflation.

Speaker: Yong Tang (University of Tokyo)

Slides KEK_Tang.pdf

16:50 Enhanced Axion-Photon Coupling in a GUT with Hidden Photon

There is a novel way to achieve the gauge coupling unification with an unbroken U(1), where the unification behavior is rather insensitive to the physics at intermediate scales. In this scheme, a hidden gauge coupling and a kinetic mixing are expected to be large. Consequently, a coupling of a QCD axion to the visible photon is significantly enhanced compared to conventional axion models. We show that this GUT scheme with the QCD axion can be testable by various future experiments.

Speaker: Norimi Yokozaki (Tohoku University)

Slides 00_KEKPH_yokozaki_v2.pdf

Wednesday, 14 February

09:00 → 10:30 Talks

Convener: Michelangelo Mangano (CERN)

09:00 Colored Dark Matter

We explore the possibility that Dark Matter is the lightest hadron made of two stable color octet Dirac fermions $\Q$. The cosmological DM abundance is reproduced for $M_\Q\approx 9.5 \TeV$, compatibly with direct searches (the Rayleigh cross section, suppressed by $1/M_\Q^6$, is close to present bounds), indirect searches (enhanced by $\Q\Q+\bar\Q\bar\Q\to \Q\bar\Q+\Q\bar\Q$ recombination), and with collider searches (where $\Q$ manifests as tracks, pair produced via QCD). Hybrid hadrons, made of $\Q$ and of SM quarks and gluons, have large QCD cross sections, and do not reach underground detectors. Their cosmological abundance is $10^5$ times smaller than DM, such that their unusual signals seem compatible with bounds. Those in the Earth and stars sank to their centers; the Earth crust and meteorites later accumulate a secondary abundance, although their present abundance depends on nuclear and geological properties that we cannot compute from first principles.

Speaker: Alessandro Strumia (Pisa U & INFN & CERN)

Slides 2017-compositeDM.pdf

09:30 Addressing theoretical uncertainties in direct dark matter searches

The interpretation of any experiment probing the dark matter distribution inside the Solar System is subject to our ignorance of the local dark matter density and velocity distribution, as well as our ignorance of the nature and strength of the dark matter-nucleon interaction. In this talk we present new ideas to interpret the outcome of direct detection experiments without making assumptions of the velocity distribution, and to confront a positive signal to a null search experiment in a halo-independent and model-independent manner.

Speaker: Ibarra Alejandro (Technical University of Munich)

Slides Ibarra.pdf

10:00 Recent PandaX-II Results on Dark Matter Search and PandaX-4T Upgrade Plan

PandaX experiment, located at China JinPing underground Laboratory (CJPL), is a 500kg scale liquid xenon dark matter direct detection experiment. With the first 98.7-day data, PandaX-II experiment obtained stringent upper limits on the spin-independent (SI) and spin-dependent (SD) WIMP-nucleon elastic scattering cross sections. Alternative models of dark matter are also explored using this data. Meanwhile, PandaX collaboration has launched an upgrade plan to build PandaX-4T detector with 4-ton liquid xenon in the active volume. The PandaX-4T experiment will be relocated to CJPL-II and is expected to run after 2020. Detailed simulation indicates that the sensitivity on SI WIMP-nucleon scattering cross section could reach 10^{-47} cm^2 after two-year's running

Speaker: Ning Zhou (Shanghai Jiao Tong University)

Slides PandaX4_KEK_20180214.pdf

10:30 → 11:00 Tea Time

11:00 → 12:00 Talks

Convener: Matthew Reece (Harvard University)

11:00 Higgs precision: a window to new physics

Speaker: Kentarou Mawatari

Slides 1802kek_mawatari_2.pdf

11:30 Analytic Boosted Boson Discrimination at the LHC

In this talk I will discuss recent progress in the area of jet substructure at the LHC, focusing in particular on analytic calculations of jet substructure observables of current interest.

Speaker: Ian Moult (Berkeley)

Slides IanMoult_KEK_2018.pdf

12:00 → 12:10 Group Photo

12:10 → 13:30 Lunch

13:30 → 15:30 Talks

Convener: Kentarou Mawatari

13:30 SM, Higgs, and BSM Physics at CMS

Speaker: Christopher Neu (University of Virginia)

Slides

• neu_CMS_physics_overview_v5.z01
• neu_CMS_physics_overview_v5.z02
• neu_CMS_physics_overview_v5.zip

14:20 Latest SM results with the ATLAS detector (including SM-Higgs)

The precise measurement of SM observables is a key element of the LHC programme, both as a probe of the fundamental properties of Nature and as a tool to improve future experimental and theoretical studies. This talk reviews the recent highlights in the measurement of SM processes, including the SM-Higgs properties, performed thanks to the ATLAS experiment.

Speaker: Federico Sforza (Tufts University)

Slides KEKPH_Atlas_SM_sforza.pdf

14:55 Latest BSM results with the ATLAS detector

Speaker: Arturo Sanchez Pineda (Universita di Udine, ICTP and CERN)

Slides Latest_BSM__results_with_the_ATLAS_detector-KEK2018-February13-17_2018_2.pdf

15:30 → 16:00 Tea Time

16:00 → 17:00 Short Talks

Convener: Terada Takahiro (KEK)

16:00 Weak Gravity Conjecture, Multiple Point Principle and the Standard Model Landscape

The requirement for an ultraviolet completable theory to be well-behaved upon compactification has been suggested as a guiding principle for distinguishing the landscape from the swampland. Motivated by the weak gravity conjecture and the multiple point principle, we investigate the vacuum structure of the standard model compactified on S^1$ and T^2. The measured value of the Higgs mass implies, in addition to the electroweak vacuum, the existence of a new vacuum where the Higgs field value is around the Planck scale. We explore two- and three-dimensional critical points of the moduli potential arising from compactifications of the electroweak vacuum as well as this high scale vacuum, in the presence of Majorana/Dirac neutrinos and/or axions. We point out potential sources of instability for these lower dimensional critical points in the standard model landscape. We also point out that a high scale AdS_4 vacuum of the Standard Model, if exists, would be at odd with the conjecture that all non-supersymmetric AdS vacua are unstable. We argue that, if we require a degeneracy between three- and four-dimensional vacua as suggested by the multiple point principle, the neutrinos are predicted to be Dirac, with the mass of the lightest neutrino O(1-10)meV, which may be tested by future CMB, large scale structure and 21cm line observations.

Speaker: Yuta Hamada (University of Wisconsin-Madison, KEK)

Slides 02_09_YutaHamada.pdf

16:20 Gravitational wave emission and oscillon formation in string axiverse

I will discuss cosmological implications of string axion dark matter whose potential has a pleateu region far from the minimum. Depending on parameters and initial values, axion self interactions can cause strong parametric resonances and, as a result, a significant amount of gravitational waves can be emitted followed by oscillon formations — a quasi-stable soliton-like object.

Speaker: Naoya Kitajima (Nagoya University)

Slides kekph2018_kitajima.pdf

16:40 A link between the EW physics and the Higgs inflation

We discuss cosmology in a scale invariant model with renormalization prescription which preserves the scale invariance even at quantum level. The difference in renormalization prescription (preserving or breaking the scale invariance) has significant impacts both on early and late time cosmology. We also discuss a theoretical aspect that such models with quantum scale invariance are non-renormalizable and hence interpreted as effective field theory. The associated cut-off scale can be higher than the Hubble scale during inflation and it’s possible to make a prediction of the inflationary observables within the effective field theory.

Speaker: Kengo Shimada (EPFL)

Slides KengoShimada-KEKPH2018.pdf

17:00 → 18:00 Poster Session

17:00 $R(D^*)$ in a general two Higgs doublet model

Speaker: Syuhei Iguro (Nagoya University)

17:00 A hidden U(1) gauge symmetry model realizing a neutrino specific two Higgs doublet model

Speaker: Takaaki Nomura (KIAS)

17:00 Correlation between the decays $h^0 \rightarrow \gamma \gamma$ and $h^0 \rightarrow g g$ in the MSSM with quark flavor violation

Speaker: Keisho Hidaka (国立大学法人 東京学芸大学)

17:00 Dark Gauge U(1) and the DAMPE Signal

Speaker: Mohammadreza Zakeri (Institute of Theoretical Physics (ITP), CAS)

17:00 Di-hadronic molecular systems

Speaker: Dharmesh Rathaud (SVNIT-Surat, India)

17:00 Dynamical scalegenesis via multiple seesaw mechanisms

Speaker: Shohei Okawa (Nagoya University)

17:00 Gravitational waves from first order electroweak phase transition in models with the $U(1)_X$ gauge symmetry

Speaker: Toshinori Matsui (KIAS)

17:00 Gravity mediation saves Universal Extra Dimensions

Speaker: Divya Sachdeva (University of Delhi)

17:00 Higgs Pair Production at Future Hadron Colliders: From Kinematics to Dynamics

Speaker: Michihisa Takeuchi (IPMU)

17:00 High-$p_T$ diphoton production near top-loop threshold

Speaker: Hiroshi Yokoya (KIAS)

17:00 Hyper Weakly Interacting light $U(1)_s$ from the String Compactifications

Speaker: Shohei Uemura (Kyoto Sangyo University)

17:00 Improved analysis for CLFV processes $\mu N(eN) \rightarrow \tau X$ with gluon operators

Speaker: Masato Yamanaka (Maskawa Institute)

17:00 Indirect test of CP violation in extended Higgs sectors by precision measurements of Higgs boson couplings

Speaker: Katsuya Hashino (University of Toyama / Osaka university)

17:00 Phenomenological study of very special relativity

Speaker: Alekha Chandra Nayak (Indian Institute of Technology, Kanpur)

17:00 Probing Higgs self-coupling of a classically scale invariant model in $e^+e^- \rightarrow Zhh$

Speaker: Yoshio Fujitani (Tohoku University)

17:00 Revisiting regularization for the Higgs mass with Kaluza-Klein states and Casimir effect from extra dimensions

Speaker: Yoshio Matsumoto (National Institute of Technology, Tsuyama College)

17:00 Signals of the gauge-Higgs unification in lepton colliders

Speaker: Yuta Orikasa (Czech Technical University)

17:00 Simultaneous interpretation of K and B anomalies in terms of chiral-flavorful vectors

Speaker: Kei Yamamoto (KMI, Nagoya University)

18:00 → 21:00 Banquet

Thursday, 15 February

09:00 → 10:30 Talks

Convener: Alessandro Strumia (Pisa U & INFN & CERN)

09:00 Naturalizing SUSY with the Relaxion and the Inflaton

The LHC Run II superpartner mass limits have exacerbated the tuning in supersymmetric extensions of the Standard Model. A possible way to explain this tuning is via a two-field relaxion mechanism, where the second field is identified with the inflaton. I will discuss the implications of the relaxion-inflaton dynamics for supersymmetry and inflation, as well as the prospects for detecting this new invisible sector in future experiments.

Speaker: Tony Gherghetta (University of Minnesota)

Slides Gherghetta_KEK-PH_2018.pdf

09:30 Distinguishing axions from WIMPs as CDM

Speaker: Sacha Davidson (IN2P3/CNRS)

Slides KEK3.pdf

10:00 Hidden sector behind the quark mixing

The small quark mixing, described by the Cabibbo-Kobayashi-Maskawa (CKM) matrix in the Standard Model, may be a clue to reveal new physics around the TeV scale. We consider a simple scenario that extra particles in a hidden sector radiatively mediate the flavor violation to the quark sector around the TeV scale and effectively realize the observed CKM matrix. The lightest particle in the hidden sector, whose contribution to the CKM matrix is expected to be dominant, is a good dark matter (DM) candidate, so we focus on the contribution, and discuss the DM physics. In this scenario, there is an explicit relation between the CKM matrix and flavor violating couplings, such as four-quark couplings, because both are radiatively induced by the particles in the hidden sector. Then, we can explicitly find the DM mass region and the size of Yukawa couplings between the DM and quarks, based on the study of flavor physics and DM physics. In conclusion, we show that DM mass in our scenario is around the TeV scale, and the Yukawa couplings are between O(0.01) and O(1). The spin-independent DM scattering cross section is estimated as O(10^-9) [pb]. We also introduce the light dark matter scenario.

Speaker: Yuji Omura (KMI, Nagoya Univ.)

Slides Omura_20180215@KEK.pdf

10:30 → 11:00 Tea Time

11:00 → 12:00 Talks

Convener: Pyungwon Ko (KIAS)

11:00 Recent developments on rare B-decays

After a review of tensions in charged-current and rare B decays and their interpretation in beyond SM scenarios, we focus on some developments that aim to improve theoretical control. Progress on QED corrections to leptonic decays B_s -> mu mu and B_u -> mu nu has been made, that was required in view of the current accuracy providing in the future precision at the percent level to short-distance quantities. A novel approach to the hadronic charm contribution in rare b-> s ll decays builds on a combined analysis of b->s ll and b-> s (ccbar) -> ll decays to separate hadronic contributions from new physics signals.

Speaker: Christoph Bobeth (Technical University Munich)

Slides flavor-KEK-TH-bobeth.pdf

11:30 Neutrino Oscillation Experiments and Recent Results from T2K

Non-zero mass of the neutrinos was proved by the discovery of neutrino oscillations in 1998. Further precision measurements of the neutrino oscillations lead to understanding the matter-antimatter asymmetry of the universe. This talk provides overview of neutrino oscillations and the experimental results that contribute to measuring the oscillation parameters. Recent results and the future prospects of T2K will be given.

Speaker: Konosuke Iwamoto (University of Tokyo)

Slides KEKPH_kiwamoto_02152018.pdf

12:00 → 13:30 Lunch

13:30 → 15:30 Short Talks

Convener: Yuji Omura (KMI, Nagoya Univ.)

13:30 Quark jet fraction in multi-jet final states and quark gluon discrimination

We calculate quark and gluon jet fraction in multi-jet final states based on perturbative QCD at double logarithmic accuracy. We derive a measurable scaling pattern of the fraction, which is related to a performance for quark-gluon jet tagging technique using QCD jet substructure. We also propose a data-driven method to use the tagging technique in large jet multiplicity.

Speaker: Yasuhito Sakaki (KAIST)

Slides KEKPH_SAKAKI.pdf

13:50 Searching for resonances in the Higgs cascade decay

We investigate the Higgs cascade decay in the extended Higgs sector. We considered the process $pp \rightarrow H^{0} \rightarrow H^{\pm}W^{\mp} \rightarrow btw$ where $H^{0}$ is heavy Higgs boson, $H^{\pm}$ is charged Higgs boson. The final state is same as $t\bar{t}$ process but the kinematic properties are different. We develop the technique using difference of kinematic properties and multivariable analysis. Our analysis technique improve the sensitivity and may give the possibility to discover the additional Higgs at the LHC or HL-LHC.

Speaker: Dong Woo Kang (Yonsei University)

Slides DWK_KEK-PH2018_3.pdf

14:10 The top threshold effect in the $\gamma\gamma$ production at the LHC

We compute the top quark threshold contributions to the $\gamma\gamma$ production at the LHC. These contributions become significant when the invariant mass of the photon pair, $M_{\gamma\gamma}$ just exceeds two times the mass of the top quark and induce some features in the $M_{\gamma\gamma}$ distribution. We determine the magnitude of this threshold effect and investigate other kinematic cuts which may enhance its significance.

Speaker: Prasenjit Sanyal (Indian Institute of Technology Kanpur)

Slides PRASENJIT_SANYAL_KEK_2018.pdf

14:30 H-COUP : Higher order calculations of Higgs observables in various extended Higgs sectors

Recently, we calculated one-loop corrected Higgs boson couplings in various extended Higgs models, such as the Higgs singlet model, two Higgs doublet models and the inert doublet model (H-COUP project). In this calculation, we used the improved on-shell scheme such that the gauge dependence does not appear in the renormalized Higgs boson couplings. Furthermore, applying this calculation of Higgs boson couplings, we have evaluated the Higgs boson decay widths including the NLO EW and QCD corrections. In this talk, we introduce the H-COUP project and discuss how we can discriminate extended Higgs models by detecting deviations from the standard model in Higgs observables at future precision measurements.

Speaker: Kodai Sakurai (University of Toyama/ Osaka University)

Slides sakurai.pdf

14:50 The Reach of Thermal Supersymmetric Dark Matter

Although the relic density of supersymmetric dark matter is often much too high, it can be reduced through several processes. One of these processes, stop coannihilation, is very efficient at reducing the dark matter density. This process’s efficiency comes because of an enhancement to the stop anti stop scattering rate the final state is the longitudinal mode of the W or Z boson. Since the coupling of the stops to the Goldstone bosons is proportional to the A-terms, this scattering can be drastically enhanced for large A-terms. If the A-terms are too large, however, the Higgs mass will be suppressed and the stop coannihilation strip is not viable. Due to uncertainties in the Higgs mass calculators, it is unclear whether this really is an important constraint on the stop coannihilation strip. Taking the most up to date Higgs mass calculator and CMSSM input parameters, it is seen that the Higgs mass constraint excluded much of the stop coannihilation strip with larger values of the LSP mass. If sub-GUT type models are considered, the reduced running softens the effect of the large A-terms allowing large LSP masses to be consistent with the Higgs mass calculation.

Speaker: Jason Evans (KIAS)

Slides StopCoKEK2_13_2018.pdf

15:30 → 15:50 Tea Time

15:50 → 17:30 Short Talks

Convener: Yasuhito Sakaki (KAIST)

15:50 Gluino-mediated electroweak penguin with flavor-violating trilinear couplings

In light of a discrepancy of the direct CP violation in K\to\pi\pi decays, \epsilon'/\epsilon_K, we investigate gluino contributions to the electroweak penguin, where flavor violations are induced by squark trilinear couplings. Top-Yukawa contributions to \Delta S=2 observables are taken into account, and vacuum stability conditions are evaluated in detail. It is found that this scenario can explain the discrepancy of \epsilon'/\epsilon_K for the squark mass smaller than 5.6 TeV. We also show that the gluing contributions can amplify Br(K\to \pi\nu\bar{\nu}), Br(K_S\to \mu^+ \mu^-)_{Jeff} and \Delta A_{CP}(b\tps\gamma). Such large effects could be measured in future experiments.

Speaker: Daiki Ueda (Sokendai)

Slides KEK-PH2018_ueda.pdf

16:10 LHCb anomaly and B physics in flavored Z′ models with flavored Higgs doublets

We study an extended Standard Model with a gauged U(1)′ flavor symmetry, motivated not only by the fermion mass hierarchy but also by the excesses in B→K(∗)ll reported by the LHCb collaborations. The U(1)′ charges are assigned to quarks and leptons in a flavor-dependent manner, and flavored Higgs doublets are also introduced in order to detail the Yukawa couplings at the renormalizable level. Then, the fermion mass hierarchy is realized by the vacuum alignment of the Higgs doublets. In this model, flavor-changing currents involving the gauge boson of U(1)′ and the scalars generated by the Higgs doublets are predicted and the observables in the B→K(∗)ll process possibly deviate from the Standard Model predictions. We study the possibility that these new flavor-changing interactions can explain the excesses in the B→K(∗)ll process, and we derive some predictions for the other flavor-violating processes based on the analysis. We specifically investigate the ΔF=2 processes and the other B decays: e.g., B→Xsγ and B→D(∗)τν, where the deviations are reported by the Belle and BABAR collaborations.

Speaker: Yoshihiro Shigekami (Nagoya University)

Slides KEK-PH2018-shigekami.pdf

16:30 Effective Higgs-nucleon coupling from lattice QCD

I will present the results of a new lattice QCD calculation of the u, d, s and heavy-quark, nucleon sigma terms with full control over all sources of uncertainty. These are important, for instance, for interpreting the results of WIMP dark matter searches or for the study of lepton-flavor violating, coherent, nuclear $\mu\to e$ conversion.

Speaker: Laurent Lellouch (CNRS and Aix-Marseille U.)

Slides lellouch.pdf

16:50 Model independent evaluation of the Wilson coefficient of the Weinberg oparator in QCD

We derive a Wilson coefficient of a CP-violating purely gluonic dimension-6 operator called the Weinberg operator (GGG~) generated by a scalar and two fermions at the two-loop level. We do not specify the representation of SU(3)$_c$ for the scalar and the fermions, and thus our result can be applied to a variety of models beyond the standard model. We estimate the nucleon EDMs induced by the Weinberg operator in some examples and discuss the importance of measuring EDMs. It is found that future measurements of the EDMs can probe physics at higher energy scale beyond the reach of collider experiments.

Speaker: Tomohiro Abe (Nagoya University)

Slides Tomohiro-Abe_kek-ph2018.pdf

17:10 Ab initio study of HVP contributions to anomalous magnetic moments of all leptons

We present the latest lattice QCD results by the BMW collaboration for the leading-order contribution of the hadron vacuum polarization (LO-HVP) to anomalous magnetic moments (g-2) of all charged leptons. Our first principle predictions without recourse to any experimental inputs provide an independent crosscheck of phenomenological approaches and important indications for assessing the agreement of the standard model prediction for the muon (g-2) with its measurement at ongoing/forthcoming experiments at Fermilab/JPARC. Calculations are performed with u, d, s and c quarks at their physical masses, in volumes of larger than 6 fm, and at six values of the lattice spacing, allowing for well-controlled continuum extrapolations, for both connected and disconnected diagrams. Systematic uncertainties are thoroughly discussed and comparisons with phenomenological estimates are made.

Speaker: Kohtaroh Miura (CPT, Aix-Marseille Universite)

Slides kek_2018feb_2.pdf

Friday, 16 February

09:00 → 10:30 Talks

Convener: Tony Gherghetta (University of Minnesota)

09:00 Unification from Scattering Amplitudes

Speaker: Clifford Cheung (Caltech)

Slides Unification_from_Scattering_Amplitudes_(Short).pdf

09:30 Cosmology of a Fine-Tuned SUSY Higgs

I will discuss some work in progress that explores whether a mildly fine-tuned Higgs boson, as in (mini-)split supersymmetry, can have interesting or observable cosmological consequences. As moduli fields oscillate, the Higgs can respond and perhaps acquire very large values along a D-flat direction. Possible consequences involve a burst of gravitational wave production and an altered estimate of the number of e-folds of inflation.

Speaker: Matthew Reece (Harvard University)

Slides Reece_KEK-PH2018_2.pdf

10:00 An Update on Supersymmetric String Landscape

Speaker: Taizan Watari (Kavli IPMU, the University of Tokyo)

Slides 18Feb16(KEKph)-watari.pdf

10:30 → 11:00 Tea Time

11:00 → 12:00 Short Talks

Convener: Sacha Davidson (IN2P3/CNRS)

11:00 Search for Dark Neutrino via Vacuum Magnetic Birefringence Experiment

We consider a dark matter model where a dark matter candidate couples to photons via an extra U(1) mediator and assume that this dark matter candidate is a fermion and can couple to the mediator with parity violation. We derived a low energy effective Lagrangian including a parity violated term for light-by-light scattering by integrating out the dark matter fermion. Our focus lies on Vacuum Magnetic Birefringence Experiment to probe the dark sector. We propose the ring resonator (3-4 mirrors) with an appropriate polarization state of light in stead of a usual Fabry-Perot resonator (2 mirrors) with a conventional polarization state of light to measure the Parity violated term. We assume that a dark neutrino is a dark matter, i.e. V-A current, and give constraints on model parameters from a current experimental limit. PTEP 2017 no. 12, 123B03 (2017) (arXiv:1707.03308 [hep-ph]), arXiv:1707.03609 [hep-ph]

Speaker: Kimiko Yamashita (Ochanomizu University)

Slides 20170216_kimiko-yamashita_kek-ph2018_pdf.pdf

11:20 Majoron as the QCD axion in a radiative seesaw model

The Standard Model of particle physics can explain the phenomena up to TeV scale. However, it has some serious problems. We propose the model which solves many of them. Our model is the simple combination of the color octet radiative seesaw model and the QCD axion model. It identifies the Lepton number breaking as the PQ number's one, and the mediator in the radiative seesaw model as the colored fermion in the QCD axion model. In this talk, we explain the model and the quantitative evaluation of it. This talk is based on the paper (Phys. Rev. D 96, 075039) with Ernest Ma (University of California) and Koji Tsumura (Kyoto University).

Speaker: Takahiro Ohata (Kyoto University)

Slides KEKPH2.pdf

11:40 Probing new intra-atomic force with isotope shifts

In the development of atomic clocks, some atomic transition frequencies are measured with remarkable precision. These measured spectra may include effects of a new force mediated by a weakly interacting boson. Such effects might be distilled out from possible violation of a linear relation in isotope shifts between two transitions, as known as King's linearity, with relatively suppressed theoretical uncertainties. We discuss the experimental sensitivity to a new force in the test of the linearity as well as the linearity violation owing to higher order effects within the Standard Model. The sensitivity to new physics is limited by such effects. We have found that for Yb$^+$, the higher order effect is in the reach of future experiments. The sensitivity to a heavy mediator is also discussed. It is analytically clarified that the sensitivity becomes weaker than that in the literature. Our numerical results of the sensitivity are compared with other weak force search experiments.

Speaker: Yasuhiro Yamamoto (Yonsei University)

Slides kekph.pdf

12:00 → 13:45 Lunch

13:45 → 15:05 Talks

Convener: Motoi Endo (KEK)

13:45 Theoretical uncertainties of monojet signatures from compressed mass spectra

Speaker: Lim Sung Hak (KEK)

Slides 20180216_NLOPrecision.pdf

14:10 Probing flavour-violating decays of squarks at the LHC

We study squark decays beyond the Minimal Flavor Violation framework at the LHC. Considering mixing between the second and third generation squarks, we first provide the coverage of the current searches at the Run-1 and Run-2 of LHC in the context of a simplified model containing two active squark flavours. We then study the sensitivity of a dedicated search strategy involving leptons, jets, and missing transverse energy at the high luminosity run of LHC.

Speaker: Amit Chakraborty (KEK)

Slides nmfvLHC.pdf

14:35 Beyond the LHC: physics goals and CERN's plans for future colliders

The LHC performance continues to exceed expectations, and the experiments are entering a new high-statistics phase for their studies. The projections for the ultimate physics output of the LHC are being updated, and new plans are being drawn for next steps, with scenarios ranging from an energy upgrade of the LHC, to the construction of a new 100km circular collider facility. I will review the physics motivations that justify these future plans, and the status of the project definition.

Speaker: Michelangelo Mangano (CERN)

Slides Mangano-KEK.pdf

15:05 → 15:35 Closing