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

Session

Short Talks

13 Feb 2018, 15:50

Building 3 1F, Seminar Hall (KEK)

Conveners

Short Talks

• Fuminobu Takahashi (Tohoku University)

Short Talks: Short Talks

• Terada Takahiro (KEK)

Short Talks: Short Talks

• Yuji Omura (KMI, Nagoya Univ.)

Short Talks: Short Talks

• Yasuhito Sakaki (KAIST)

Short Talks: Short Talks

• Sacha Davidson (IN2P3/CNRS)

11. High-energy neutrinos from multi-body decaying dark matter

Nagisa Hiroshima (KEK, ICRR)

13/02/2018, 15:50

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...

12. Search for New physics with High multiplicity from High energy cosmic rays

Yongsoo Jho (Yonsei University)

13/02/2018, 16:10

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...

13. Thermal Gravitational Contribution to Dark Matter Production

Yong Tang (University of Tokyo)

13/02/2018, 16:30

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...

15. Enhanced Axion-Photon Coupling in a GUT with Hidden Photon

Norimi Yokozaki (Tohoku University)

13/02/2018, 16:50

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...

30. Weak Gravity Conjecture, Multiple Point Principle and the Standard Model Landscape

Yuta Hamada (University of Wisconsin-Madison, KEK)

14/02/2018, 16:00

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...

31. Gravitational wave emission and oscillon formation in string axiverse

Naoya Kitajima (Nagoya University)

14/02/2018, 16:20

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.

32. A link between the EW physics and the Higgs inflation

Kengo Shimada (EPFL)

14/02/2018, 16:40

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...

38. Quark jet fraction in multi-jet final states and quark gluon discrimination

Yasuhito Sakaki (KAIST)

15/02/2018, 13:30

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.

39. Searching for resonances in the Higgs cascade decay

Dong Woo Kang (Yonsei University)

15/02/2018, 13:50

We investigate the Higgs cascade decay in the extended Higgs sector. We considered the process $pp\to H^0\to H^{\pm }{W}^{\mp }\to btw$ where $H^0$ is heavy Higgs boson, $H^{\pm }$ is charged Higgs boson. The final state is same as $t\overline{t}$ process but the kinematic properties are different. We develop the technique using difference of kinematic properties and...

41. The top threshold effect in the $\gamma \gamma$ production at the LHC

Prasenjit Sanyal (Indian Institute of Technology Kanpur)

15/02/2018, 14:10

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...

42. H-COUP : Higher order calculations of Higgs observables in various extended Higgs sectors

Kodai Sakurai (University of Toyama/ Osaka University)

15/02/2018, 14:30

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...

43. The Reach of Thermal Supersymmetric Dark Matter

Jason Evans (KIAS)

15/02/2018, 14:50

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...

44. Gluino-mediated electroweak penguin with flavor-violating trilinear couplings

Daiki Ueda (Sokendai)

15/02/2018, 15:50

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...

45. LHCb anomaly and B physics in flavored Z′ models with flavored Higgs doublets

Yoshihiro Shigekami (Nagoya University)

15/02/2018, 16:10

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....

46. Effective Higgs-nucleon coupling from lattice QCD

Laurent Lellouch (CNRS and Aix-Marseille U.)

15/02/2018, 16:30

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.

47. Model independent evaluation of the Wilson coefficient of the Weinberg oparator in QCD

Tomohiro Abe (Nagoya University)

15/02/2018, 16:50

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...

48. Ab initio study of HVP contributions to anomalous magnetic moments of all leptons

Kohtaroh Miura (CPT, Aix-Marseille Universite)

15/02/2018, 17:10

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...

24. Search for Dark Neutrino via Vacuum Magnetic Birefringence Experiment

Kimiko Yamashita (Ochanomizu University)

16/02/2018, 11:00

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...

25. Majoron as the QCD axion in a radiative seesaw model

Takahiro Ohata (Kyoto University)

16/02/2018, 11:20

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...

26. Probing new intra-atomic force with isotope shifts

Yasuhiro Yamamoto (Yonsei University)

16/02/2018, 11:40

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...