Wen Yin

A bstract We propose a SUSY scenario to explain the current electron and muon g − 2 discrepancies without introducing lepton flavor mixings. Threshold corrections to the Yukawa couplings can enhance the electron g − 2 and flip the sign of the SUSY contributions. The mechanism predicts a flavor-dependent slepton mass spectrum. We show that it is compatible with the Higgs mediation scenario.

Abstract ALP domain walls without strings may be formed in the early Universe. We point out that such ALP domain walls lead to both isotropic and anisotropic birefringence of cosmic microwave background (CMB) polarization, which reflects spatial configuration of the domain walls at the recombination. The polarization plane of the CMB photon coming from each domain is either not rotated at all or rotated by a fixed angle. For domain walls following the scaling solution, the cosmic birefringence o

A bstract Several attempts to solve the cosmological constant problem, which concerns the value of the cosmological constant being extremely smaller than the Standard Model mass scales, have introduced a scalar field with a very flat potential that can be approximated as linear around any given position. The scalar field scans the cosmological constant in such a way that the current small value is explained. Recently, Dark Energy Spectroscopic Instrument (DESI) reported the results of the first

The long-standing discrepancy of the muon anomalous magnetic moment ($g\ensuremath{-}2$) is a hint of new physics beyond the standard model of particle physics. In this paper, we show that heavy new physics contribution can be fully tested at a muon collider with a center-of-mass energy up to $\mathcal{O}(10)\text{ }\text{ }\mathrm{TeV}$ with $\mathcal{O}(10)\text{ }\text{ }{\mathrm{ab}}^{\ensuremath{-}1}$. Even if there is no new particle in this energy range, one can measure the $g\ensuremath{

We study the cutoff for the cosmic-ray neutrino, set by the scattering with cosmic background neutrinos into dark sector particles through a neutrino portal interaction. We find that a large interaction rate is still viable, when the dark sector particles are mainly coupled to the τ-neutrino, so that the neutrino mean free path can be reduced to be O(10) Mpc over a wide energy range. If stable enough, the dark sector particle, into which most of the cosmic-ray neutrino energy is transferred, can

We study the formation and evolution of domain walls with initial inflationary fluctuations by numerical lattice calculations that, for the first time, correctly take into account correlations on superhorizon scales. We find that, contrary to the widely-held claim over the past few tens of years, the domain wall network exhibits remarkable stability even when the initial distribution is largely biased toward one of the minima. This is due to the fact that the domain wall network retains informat

A bstract The long-standing muon g − 2 anomaly has been confirmed recently at the Fermilab. The combined discrepancy from Fermilab and Brookhaven results shows a difference from the theory at a significance of 4.2 σ . In addition, the LHC has updated the lower mass bound of a pure wino. In this letter, we study to what extent the g − 2 can be explained in anomaly mediation scenarios, where the pure wino is the dominant dark matter component. To this end, we derive some model-independent constrai

We propose a scenario where only the Higgs multiplets have direct couplings to a supersymmetry (SUSY) breaking sector. The standard model matter multiplets as well as the gauge multiples are sequestered from the SUSY breaking sector; therefore, their masses arise via anomaly mediation at the high energy scale with a gravitino mass of ∼100TeV. Due to renormalization group running effects from the Higgs soft masses, the masses of the third generation sfermions become O(10)TeV at the low energy sca

Recently, a low-z measurement of the Hubble constant, H0=73.04±1.04km/s/Mpc, was reported by the SH0ES Team. The long-standing Hubble tension, i.e. the difference between the Hubble constant from the local measurements and that inferred from the cosmic microwave background data based on the ΛCDM model, was further strengthened. There are many cosmological models modifying the cosmology after and around the recombination era to alleviate this tension. Some of the models alter the small-scale fluc

We examine the theoretical possibility for the heavy QCD axion to induce slow-roll inflation while solving the strong CP problem through the Peccei-Quinn mechanism. If the cancellation between contributions from a small-size instanton and another Peccei-Quinn symmetry breaking occurs with high accuracy, the potential can be flattened enough near its maximum to achieve hilltop inflation. This comes at the cost of severe fine-tuning of their relative size and phase, but it also allows us to relate

A bstract The axion mass receives a large correction from small instantons if the QCD gets strongly coupled at high energies. We discuss the size of the new CP violating phases caused by the fact that the small instantons are sensitive to the UV physics. We also discuss the effects of the mass correction on the axion abundance of the Universe. Taking the small-instanton contributions into account, we propose a natural scenario of axion dark matter where the axion decay constant is as large as 10

The long-standing discrepancy of muon $g-2$ is a hint of new physics beyond the standard model of particle physics. In this letter we show that heavy new physics contribution can be fully tested at a muon collider with center-of-mass energy up to $O(10)\,$TeV. Even if there is no new particle in this energy range, one can measure the $g-2$ directly via the channel to a Higgs boson and a monochromatic photon.

We suggest a natural split mechanism for sfermions based on N=2 supersymmetry (SUSY). N=2 SUSY protects a sfermion in an N=2 multiplet from gaining weight by SUSY breaking. Therefore, if partly N=2 SUSY is effectively obtained, a split spectrum can be realized naturally. As an example of the natural split mechanism, we build a gauge-mediated SUSY breaking-like model assuming N=2 SUSY is partly broken in an underlying theory. The model explains the Higgs boson mass and muon anomalous magnetic dip

We propose a novel scenario to explain the small cosmological constant (CC) by a peculiar inflaton potential. The shape almost satisfies the following conditions: The inflation is eternal if the CC is positive and not eternal if the CC is negative. Although realizing the peculiar shape has a similar amount of fine-tuning as the CC, the shape can be made stable under radiative corrections in the effective theory. By introducing a slowly varying CC from a positive value to a negative value, the do

The identity of dark matter has been a mystery in astronomy, cosmology, and particle theory for about a century. We present the first dark matter search with a high-dispersion spectrograph by using WINERED at the 6.5 m Magellan Clay telescope to measure the photons from the dark matter decays. The dwarf spheroidal galaxies (dSphs) Leo V and Tucana II are observed by utilizing an object-sky-object nodding observation technique. Employing zero consistent flux data after the sky subtraction and per