arXiv subjects

Xinyue Yin

Publications and source records attributed to Xinyue Yin.

5 recordsLinked to original sources

arXiv2025

Illuminating sequential freeze-in dark matter with dark photon signal at the CERN SHiP experiment

Single-field freeze-in dark matter barely leaves observable footprints in dark matter direct detection, collider or fixed-target experiments, which can be altered in the two-field context. In this work, we consider sequential freeze-in dark matter through signals of dark photon mediator with a mass range of $m_{A'}\sim 10^{-2}-10$ GeV covered by the proposed SHiP experiment. We show that the dark charge is fixed to be $e'\sim 1.3\times 10^{-12}$ and the mixing parameter is restricted to $10^{-11}\leq \epsilon< 10^{-8}-10^{-7.5}$, as a result of the out-of-equilibrium condition of dark photon and the observed relic abundance of dark matter. Within this $\epsilon$ region, the 5(15)-year data of proton bremsstrahlung process for the dark photon, assuming vector meson (dipole) dominance, excludes $\epsilon\geq 10^{-8.5} (10^{-7.9})$ at 90\% confidence level, implying only a narrow region of $\epsilon$ close to $\sim 10^{-11}$ left for alternative tests.

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arXiv2024

LHC-friendly freeze-in dark matter via Higgs portal

It is known that single-field freeze-in dark matter barely leaves footprints in dark matter direct detection and collider experiments. This situation can be altered in two-field context. In this work we propose a two-field freeze-in dark matter model through Higgs portal. The observed dark matter relic abundance is obtained by a decay of scalar mediator thermalized in the early Universe. While there is a lack of direct dark matter signals, the scalar mediator is in the reach of HL-LHC either through vector boson fusion or Mono-Z channel. Within allowed scalar mass window of 10-50 GeV, we use improved cuts to derive both $2\sigma$ exclusion and $5\sigma$ discovery limits, depending on the value of Higgs portal coupling. If verified, this scalar mediator signal allows us to infer the freeze-in dark matter.

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arXiv2024

Self-interacting dark matter to freeze-in via vector portal

It is challenging to resolve the small-scale problem for dark matter being a weakly-interacting massive particle. We attempt to address this issue by proposing a self-interacting freeze-in dark matter via dark photon. In this model, the dark matter obtains the observed relic abundance via Standard Model $γ$ and $Z$ boson induced freeze-in processes, whereas the dark matter force mediator has a negligible relic abundance and a lifetime larger than the age of Universe. We place constraints in classical and resonant regime resolving the small-scale problem from CMB, $X/γ$-ray, Supernova 1987A and out-of-equilibrium condition. It turns out that the CMB constraint on dark matter annihilations is satisfied despite large Sommerfeld effect taking place, while the other constraints are trivially accommodated due to various millicharge induced suppressions. Finally we briefly discuss future cosmological tests on such freeze-in dark matter model.

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arXiv2021

Investigating the $Z^\prime$ gauge boson at the future lepton colliders

$Z^\prime$ boson as a new gauge boson has been proposed in many new physics models. The interactions of $Z^\prime$ coupling to fermions are detailed studied at the large hadron collider. A $Z^\prime$ with the mass of a few TeV has been excluded in some special models. The future lepton colliders will focus on the studies of Higgs physics which provide the advantage to investigate the interactions of Higgs boson with the new gauge bosons. We investigate the $Z^\prime ZH$ interaction via the process of $e^+e^- \to Z^\prime/Z \to ZH \to l^+l^- b \bar{b}$. The angular distribution of the final leptons decaying from the $Z$-boson is related to the mixing of $Z^\prime$-$Z$ and the mass of $Z^\prime$. The forward-backward asymmetry has been proposed as an observable to investigate the $Z^\prime$-$Z$ mixing. The angular distributions change significantly with some special beam polarization comparing to the unpolarized condition.

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arXiv2021

$D^*$ meson production in jet from combination of charm quark with light one

In the framework of the perturbative Quantum Chromodynamics factorization, the cross section of the heavy meson production via the combination of a heavy quark with a light one can be factorized to be the convolution of the combination matrix element, the light quark distribution function, and the hard partonic sub-cross section of the heavy quark production. The partonic distribution and the combination matrix element are functions of a scaling variable, respectively, which is the momentum fraction of the corresponding quark with respect to the heavy meson. We studied the $D^{*\pm}$ production in jet via combination in pp collision at the LHC. Our calculation can be summed with the fragmentation contribution, and the total result is comparable with the experimental data. The combination matrix elements can be further studied in various hadron production processes.

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