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Shin-Shan Yu

Publications and source records attributed to Shin-Shan Yu.

15 recordsLinked to original sources

t-channel dark matter at the LHC -- a whitepaper

This report, summarising work achieved in the context of the LHC Dark Matter Working Group, investigates the phenomenology of $t$-channel dark matter models, spanning minimal setups with a single dark matter candidate and mediator to more complex constructions closer to UV-complete models. For each considered class of models, we examine collider, cosmological and astrophysical implications. In addition, we explore scenarios with either promptly decaying or long-lived particles, as well as featuring diverse dark matter production mechanisms in the early universe. By providing a unified analysis framework, numerical tools and guidelines, this work aims to support future experimental and theoretical efforts in exploring $t$-channel dark matter models at colliders and in cosmology.

hep-ph

First Results from the Taiwan Axion Search Experiment with Haloscope at 19.6 $\mu$eV

This Letter reports on the first results from the Taiwan Axion Search Experiment with Haloscope, a search for axions using a microwave cavity at frequencies between 4.70750 and 4.79815 GHz. Apart from the non-axion signals, no candidates with a significance more than 3.355 were found. The experiment excludes models with the axion-two-photon coupling $\left|g_{a\gamma\gamma}\right|\gtrsim 8.2\times 10^{-14}$ GeV$^{-1}$, a factor of eleven above the benchmark KSVZ model, reaching a sensitivity three orders of magnitude better than any existing limits in the mass range 19.4687 < $m_a$ < 19.8436 $\mu$eV. It is also the first time that a haloscope-type experiment places constraints on $g_{a\gamma\gamma}$ in this mass region.

hep-ex

Taiwan Axion Search Experiment with Haloscope: Designs and operations

We report on a holoscope axion search experiment near $19.6\ {\rm \mu eV}$ from the TASEH collaboration. The experiment is carried out via a frequency-tunable cavity detector with a volume $V = 0.234\ {\rm liter}$ in a magnetic field $B_0 = 8\ {\rm T}$. With a signal receiver that has a system noise temperature $T_{\rm sys} \cong 2.2\ {\rm K}$ and experiment time about 1 month, the search excludes values of the axion-photon coupling constant $g_{\rm a\gamma\gamma} \gtrsim 8.1 \times 10^{-14} \ {\rm GeV}^{-1}$, a factor of 11 above the KSVZ model, at the 95\% confidence level in the mass range of $19.4687-19.8436\ {\rm \mu eV}$. We present the experimental setup and procedures to accomplish this search.

physics.ins-det

Taiwan Axion Search Experiment with Haloscope: CD102 Analysis Details

This paper presents the analysis of the data acquired during the first physics run of the Taiwan Axion Search Experiment with Haloscope (TASEH), a search for axions using a microwave cavity at frequencies between 4.70750 and 4.79815 GHz. The data were collected from October 13, 2021 to November 15, 2021, and are referred to as the CD102 data. The analysis of the TASEH CD102 data excludes models with the axion-two-photon coupling $|g_{a\gamma\gamma}| \gtrsim 8.2\times 10^{-14}$ GeV$^{-1}$, a factor of eleven above the benchmark KSVZ model for the mass range 19.4687 < ma < 19.8436 $\mu$eV.

hep-ex

Jets and Jet Substructure at Future Colliders

Even though jet substructure was not an original design consideration for the Large Hadron Collider (LHC) experiments, it has emerged as an essential tool for the current physics program. We examine the role of jet substructure on the motivation for and design of future energy frontier colliders. In particular, we discuss the need for a vibrant theory and experimental research and development program to extend jet substructure physics into the new regimes probed by future colliders. Jet substructure has organically evolved with a close connection between theorists and experimentalists and has catalyzed exciting innovations in both communities. We expect such developments will play an important role in the future energy frontier physics program.

hep-ph

LHC Dark Matter Working Group: Next-generation spin-0 dark matter models

Dark matter (DM) simplified models are by now commonly used by the ATLAS and CMS Collaborations to interpret searches for missing transverse energy ($E_T^\mathrm{miss}$). The coherent use of these models sharpened the LHC DM search program, especially in the presentation of its results and their comparison to DM direct-detection (DD) and indirect-detection (ID) experiments. However, the community has been aware of the limitations of the DM simplified models, in particular the lack of theoretical consistency of some of them and their restricted phenomenology leading to the relevance of only a small subset of $E_T^\mathrm{miss}$ signatures. This document from the LHC Dark Matter Working Group identifies an example of a next-generation DM model, called $\textrm{2HDM+a}$, that provides the simplest theoretically consistent extension of the DM pseudoscalar simplified model. A comprehensive study of the phenomenology of the $\textrm{2HDM+a}$ model is presented, including a discussion of the rich and intricate pattern of mono-$X$ signatures and the relevance of other DM as well as non-DM experiments. Based on our discussions, a set of recommended scans are proposed to explore the parameter space of the $\textrm{2HDM+a}$ model through LHC searches. The exclusion limits obtained from the proposed scans can be consistently compared to the constraints on the $\textrm{2HDM+a}$ model that derive from DD, ID and the DM relic density.

hep-ex

Search for Dark Matter in pp Collisions with CMS

Searches in CMS for dark matter in final states with invisible particles recoiling against jets, top, W, Z, photon, and Higgs are presented. Various topologies are explored, covering several specific dark-matter production modes. The summary in a simplified-model framework of various searches for direct dark matter production with the CMS detector is discussed, highlighting sensitivities of the analyses under various assumptions of DM production.

hep-ex

Study Of Boosted W-Jets And Higgs-Jets With the SiFCC Detector

We study the detector performance in the reconstruction of hadronically-decaying W bosons and Higgs bosons at very high energy proton colliders using a full GEANT4 simulation of the SiFCC detector. The W and Higgs bosons carry transverse momentum in the multi-TeV range, which results in collimated decay products that are reconstructed as a single jet. We present a measurement of the energy response and resolution of boosted W-jets and Higgs-jets and show the separation of two sub-jets within the boosted boson jet.

hep-ex

Review of Recent Tevatron Jet, W/Z+Jet and Heavy-flavor Production Results

This document reviews several recent measurements at the Fermilab Tevatron, including the cross sections of inclusive jet, dijet production, the cross sections of electroweak boson (W or Z) production in association with inclusive or heavy-flavor (b or c) jets, and b-jet shapes. In addition, searches for new physics using the dijet angular distributions are discussed. These analyses are based on integrated luminosities of 0.3--2.5/fb of p-pbar collisions at \sqrt{s}=1.96 TeV, collected with the CDF and D0 detectors. The results directly test the leading order and next-to leading order calculations of perturbative quantum chromodynamics and provide constraints on the parton distribution functions, gluon-splitting contribution, and physics beyond the standard model.

hep-ex

Searches for New Physics at the Tevatron in Photon and Jet Final States

We present the results of searches for non-standard model phenomena in photon and jet final states. These searches use data from integrated luminosities of 0.7--2.7/fb of p-pbar collisions at sqrt(s)=1.96 TeV, collected with the CDF and D0 detectors at the Fermilab Tevatron. No significant excess in data has been observed. We report limits on the parameters of several models, including: large extra dimension, compositeness, leptoquarks, and supersymmetry.

hep-ex

Search for Anomalous Production of Photon, b-jet, and Missing Transverse Energy at CDF

We report the results of two signature-based searches for new physics using 1.9- 2.0 fb-1 of data collected at the CDF experiment. Both analyses look in events containing a photon, a b-tagged jet, and missing transverse energy. The first search requires an additional jet. The second search requires an extra electron or muon. No significant excess of events over the Standard Model prediction is observed. We also describe the "CES/CPR" method which is used to estimate the amount of mis-identified photons.

hep-ex

Other Beyond Standard Model Searches at the Tevatron

We present the results of searches for non-standard model phenomena, with focus on signature-based searches and searches driven by non-supersymmetry (non-SUSY) models. The analyses use 1.0--2.5 fb-1 of data from ppbar collisions at sqrt(s)=1.96 TeV collected with the CDF and D0 detectors at the Fermilab Tevatron. No significant excess in data has been observed. We report on the event counts, kinematic distributions, and limits on selected model parameters.

hep-ex

Search for New Physics with Photons at the Tevatron

We report on a search for compositeness in ee+gamma events and a search for gauge-mediated supersymmetry in gamma+gamma+met events. We also report on two signature-based searches for anomalous production of gamma + gamma + X (where X=e, mu, gamma, met) and gamma + lepton + X. The analyses are based on 0.9--1.2 fb-1 of data from p-pbar collisions at sqrt(s)=1.96 TeV collected with the CDF and D0 detectors at the Fermilab Tevatron. No significant excess of data over the predicted background has been observed.

hep-ex

Search for Higgs at CDF

We present the results on the searches for the SM and the non-SM Higgs boson production in ppbar collisions at sqrt(s)=1.96 TeV with the CDF detector at the Fermilab Tevatron. Using data corresponding to 300--700pb-1, we search for the Higgs boson in various production and decay channels. No signal is observed, therefore, we set upper limits on the production cross-section times branching fraction as a function of the Higgs boson mass.

hep-ex

First Measurement of the Ratio of Branching Fractions BR(LAMBDAB to Lambdac Mu Nu)/BR(LAMBDAB to Lambdac Pi) at CDF II

We present the first measurement of the ratio of branching fractions BR(LAMBDAB TO LAMBDAC MU NU)/BR(LAMBDAB to LAMBDAC PI) based on 171.5 pb-1 of ppbar collisions at the center of mass energy 1.96 TeV taken with the CDF-II detector. In addition, we present measurements of BR(B0 TO DSTAR MU NU)/BR(B0 TO DSTAR PI) and BR(B0 TO D MU NU)/BR(B0 TO D PI), which serve as control samples to understand the data and Monte Carlo used for the Lambdab analysis. We find the relative branching fractions of the control samples are consistent with the ratios obtained by the Particle Data Group at the 0.7 and 1.1 sigma level, respectively. Finally, we obtain the relative Lambdab branching fraction to be: BR(LAMBDAB TO LAMBDAC MU NU)/BR(LAMBDAB to LAMBDAC PI)=20.0 +- 3.0 (stat) +- 1.2 (syst) + 0.7 -2.1 (BR) +- 0.5 (UBR). The uncertainties of the three relative branching fractions are from statistics, CDF internal systematics, external measured branching ratios and unmeasured branching ratios, respectively. We present a method to derive BR(LAMBDAB TO LAMBDAC PI) using previous CDF measurements and obtain BR(LAMBDAB TO LAMBDAC PI) = (0.41 +- 0.19 (stat + syst) + 0.06 -0.08 (pt))%, where the last uncertainty is due to the measured Lambdab pt spectrum. Combining with our result, we determine the exclusive semileptonic branching fraction for the Lambdab= (8.1 +- 1.2 (stat) + 1.1 -1.6 (syst) +- 4.3 (BR(LAMBDAB TO LAMDAC PI)))%

hep-ex