arXiv subjects

Tianyang Shen

Publications and source records attributed to Tianyang Shen.

4 recordsLinked to original sources

arXiv2024

TeV-scale Lepton Number Violation: Connecting Leptogenesis, Neutrinoless Double Beta Decay, and Colliders

In the context of TeV-scale lepton number violating (LNV) interactions, we illustrate the interplay between leptogenesis, neutrinoless double beta ($0νββ$) decay, and LNV searches at proton-proton colliders. Using a concrete model for illustration, we identify the parameter space where standard thermal leptogenesis is rendered unviable due to washout processes and show how $0νββ$ decay and $pp$ collisions provide complementary probes. We find that the new particle spectrum can have a decisive impact on the relative sensitivity of these two probes.

hep-ph↗

arXiv2022

Uncovering a chirally suppressed mechanism of $0νββ$ decay with LHC searches

$ΔL =2$ lepton number violation (LNV) at the TeV scale could provide an alternative interpretation of positive signal(s) in future neutrinoless double beta $(0νββ)$ decay experiments. An interesting class of models from this point of view are those that at low energies give rise to dimension-9 vector operators and a dimension-7 operator, both of whose $0νββ$-decay rates are "chirally suppressed". We study and compare the sensitivities of $0νββ$-decay experiments and LHC searches to a simplified model in this class of TeV-scale LNV that is also $SU(2)_L \times U(1)_Y$ gauge invariant. The searches for $0νββ$ decay, which are here diluted by a chiral suppression of the vector operators, are found to be less constraining than LHC searches whose reach is increased by the assumed kinematic accessibility of the mediator particles. For the chirally suppressed dimension-7 operator generated by TeV-scale mediators, in contrast, $0νββ$-decay searches place strong constraints on the size of the new Yukawa coupling. Signals of this model at the LHC and $0νββ$-decay experiments are entirely uncorrelated with the observed neutrinos masses, as these new sources of LNV give negligible contributions to the latter. We find the prospects for the high-luminosity LHC and ton-scale $0νββ$-decay experiments to uncover the chirally-suppressed mechanism with TeV-scale LNV to be promising. We also comment on the sensitivity of the $0νββ$-decay lifetime to certain unknown low-energy constants that in the case of dimension-9 {\it scalar} operators are expected to be large due to non-perturbative renormalization.

hep-ph↗

arXiv2021

Reputation dependent pricing strategy: analysis based on a Chinese C2C marketplace

Most online markets establish reputation systems to assist building trust between sellers and buyers. Sellers' reputations not only provide guidelines for buyers but may also inform sellers their optimal pricing strategy. In this research, we assumed two types of buyer: informed buyers and uninformed buyers. Informed buyers know more about the reputation about the seller but may incur a search cost. Then we developed a benchmark model and a competition model. We found that high reputation sellers and low reputation sellers adapt different pricing strategy depending on the informativeness of buyers and the competition among sellers. With a large proportion of informed buyers, high reputation sellers may charge lower price than low reputation sellers, which exists a negative price premium effect, in contrast to conclusions of some previous studies. Empirical findings were in consistence with our theoretical models. We collected data of five categories of products, televisions, laptops, cosmetics, shoes, and beverages, from Taobao, a leading C2C Chinese online market. Negative price premium effect was observed for TVs, laptops, and cosmetics; price premium effect was observed for beverages; no significant trend was observed for shoes. We infer product value and market complexity are the main factors of buyer informativeness.

econ.GN↗

arXiv2018

Electric Dipole Moments from CP-Violating Scalar Leptoquark Interactions

We analyze the implications of CP-violating scalar leptoquark (LQ) interactions for experimental probes of parity- and time-reversal violating properties of polar molecules. These systems are predominantly sensitive to the electric dipole moment (EDM) of the electron and nuclear-spin-independent (NSID) electron-nucleon interaction. The LQ model can generate both a tree-level NSID interaction as well as the electron EDM at one-loop order. Including both interactions, we find that the NSID interaction can dominate the molecular response. For moderate values of couplings, the current experimental results give roughly two orders of magnitude stronger limits on the electron EDM than one would otherwise infer from a sole-source analysis.

hep-ph↗