oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 4 )

2019 ( 20 )

2018 ( 124 )

2017 ( 121 )

Custom range...

Search Results: 1 - 10 of 8893 matches for " Jiayin Gu "
All listed articles are free for downloading (OA Articles)
Page 1 /8893
Display every page Item
Running after Diphoton
Jiayin Gu,Zhen Liu
Physics , 2015,
Abstract: A very plausible explanation for the recently observed diphoton excess at the 13 TeV LHC is a (pseudo)scalar with mass around 750 GeV, which couples to a gluon pair and to a photon pair through loops involving vector-like quarks (VLQs). To accommodate the observed rate, the required Yukawa couplings tend to be large. A large Yukawa coupling would rapidly run up with the scale and quickly reach the perturbativity bound, indicating that new physics, possibly with a strong dynamics origin, is near by. The case becomes stronger especially if the ATLAS observation of a large width persists. In this paper we study the implication on the scale of new physics from the 750 GeV diphoton excess using the method of Renormalization Group running with careful treatment of different contributions and perturbativity criterion. Our results suggest that the scale of new physics is generically not much larger than the TeV scale, in particular if the width of the scalar is large. Introducing multiple copies of VLQs, lowing the VLQ masses (~ 400 GeV) and enlarging VLQ electric charges (to 5/3) help reduce the required Yukawa couplings and can push the cutoff scale to higher values. Nevertheless, if the width of the 750 GeV resonance turns out to be larger than about 1 GeV, it is very hard to increase the cutoff scale beyond a few TeVs. This is a strong hint that new particles in addition to the 750 GeV resonance and the vector like quarks should be around the TeV scale.
Supermolecular Interaction of Ferrocenium with Yeast DNA and Application in Electrochemical Sensing for Hybridization Recognition of Yeast DNA
Huangxian Ju,Baofen Ye,Jiayin Gu
Sensors , 2004, DOI: 10.3390/s40500071
Abstract: The supermolecular interactions of single-stranded yeast DNA (ssDNA) and double-stranded DNA (dsDNA) with ferrocenium (Fc+) both in solution and at the electrode/solution interface were studied with UV spectroscopy and electrochemical method. The interaction of covalently immobilized dsDNA with Fc+ resulted in a change of the electrode behavior from diffusion-controlled to surface-controlled and an increase in the current response of Fc+ reduction, which has been used to develop a novel electrochemical yeast DNA sensor for hybridization recognition of immobilized yeast ssDNA to its complementary ssDNA (cDNA). The adsorption constants of Fc+ on ssDNA and dsDNA modified gold electrode surface were (3.38±0.04)×103 M-1 and (2.02±0.02)×104 M-1, respectively, indicating a higher affinity of dsDNA to Fc+. UV spectra and the influence of ion strength showed that the interaction mode between Fc+ and dsDNA in solution might be a groove binding. The interaction between Fc+ and immobilized DNA was mainly an electrostatic model.
Measuring Invisible Particle Masses Using a Single Short Decay Chain
Hsin-Chia Cheng,Jiayin Gu
Physics , 2011, DOI: 10.1007/JHEP10(2011)094
Abstract: We consider the mass measurement at hadron colliders for a decay chain of two steps, which ends with a missing particle. Such a topology appears as a subprocess of signal events of many new physics models which contain a dark matter candidate. From the two visible particles coming from the decay chain, only one invariant mass combination can be formed and hence it is na\"ively expected that the masses of the three invisible particles in the decay chain cannot be determined from a single end point of the invariant mass distribution. We show that the event distribution in the $\log(E_{1T}/E_{2T})$ vs. invariant mass-squared plane, where $E_{1T}$, $E_{2T}$ are the transverse energies of the two visible particles, contains the information of all three invisible particle masses and allows them to be extracted individually. The experimental smearing and combinatorial issues pose challenges to the mass measurements. However, in many cases the three invisible particle masses in the decay chain can be determined with reasonable accuracies.
A Toolkit of the Stop Search via the Chargino Decay
Bai, Yang;Cheng, Hsin-Chia;Gallicchio, Jason;Gu, Jiayin
High Energy Physics - Phenomenology , 2013,
Abstract: The top squark (stop) may dominantly decay to a bottom quark and a chargino if the mass difference between the stop and the lightest neutralino is comparable or less than the top quark mass. Such a moderately compressed spectrum is a challenging scenario for the stop search at the Large Hadron Collider, because it is difficult to separate the signals from the top and anti-top background. In this paper we focus on the di-leptonic decay channel, and consider many kinematic variables as possible discriminators. These include several MT2 variables and new "compatible-masses" variables which fully utilize all kinematic information of the background. We use several sample spectra with different characteristics to study the efficiencies of these variables in distinguishing the signal from the background. The finding is that different combinations of variables or strategies should be used for different spectra to maximally enhance the signal significance and expand the reach of the stop search in this scenario. The new variables that we proposed in this paper are also useful for other new physics searches with di-leptonic top and anti-top events as the dominant background.
Stop the Top Background of the Stop Search
Yang Bai,Hsin-Chia Cheng,Jason Gallicchio,Jiayin Gu
Physics , 2012, DOI: 10.1007/JHEP07(2012)110
Abstract: The main background for the supersymmetric stop direct production search comes from Standard Model ttbar events. For the single-lepton search channel, we introduce a few kinematic variables to further suppress this background by focusing on its dileptonic and semileptonic topologies. All are defined to have end points in the background, but not signal distributions. They can substantially improve the stop signal significance and mass reach when combined with traditional kinematic variables such as the total missing transverse energy. Among them, our variable M^W_T2 has the best overall performance because it uses all available kinematic information, including the on-shell mass of both W's. We see 20%-30% improvement on the discovery significance and estimate that the 8 TeV LHC run with 20 fb-1 of data would be able to reach an exclusion limit of 650-700 GeV for direct stop production, as long as the stop decays dominantly to the top quark and a light stable neutralino. Most of the mass range required for the supersymmetric solution of the naturalness problem in the standard scenario can be covered.
Beyond Higgs Couplings: Probing the Higgs with Angular Observables at Future $e^+ e^-$ Colliders
Nathaniel Craig,Jiayin Gu,Zhen Liu,Kechen Wang
Physics , 2015,
Abstract: We study angular observables in the $e^+e^-\to Z H\to \ell^+ \ell^-\,b\bar{b}$ channel at future circular $e^+ e^-$ colliders such as CEPC and FCC-ee. Taking into account the impact of realistic cut acceptance and detector effects, we forecast the precision of six angular asymmetries at CEPC (FCC-ee) with center-of-mass energy $\sqrt{s} =$ 240 GeV and 5 (30) ${\rm ab}^{-1}$ integrated luminosity. We then determine the projected sensitivity to a range of operators relevant for the Higgs-strahlung process in the dimension-6 Higgs EFT. Our results show that angular observables provide complementary sensitivity to rate measurements when constraining various tensor structures arising from new physics. We further find that angular asymmetries provide a novel means of both probing BSM corrections to the $H Z \gamma$ coupling and constraining the "blind spot" in indirect limits on supersymmetric scalar top partners.
Higgs mass from compositeness at a multi-TeV scale
Hsin-Chia Cheng,Bogdan A. Dobrescu,Jiayin Gu
Physics , 2013, DOI: 10.1007/JHEP08(2014)095
Abstract: Within composite Higgs models based on the top seesaw mechanism, we show that the Higgs field can arise as the pseudo Nambu-Goldstone boson of the broken U(3)_L chiral symmetry associated with a vector-like quark and the t-b doublet. As a result, the lightest CP-even neutral state of the composite scalar sector is lighter than the top quark, and can be identified as the newly discovered Higgs boson. Constraints on weak isospin violation push the chiral symmetry breaking scale above a few TeV, implying that other composite scalars are probably too heavy to be probed at the LHC, but may be within reach at a future hadron collider with center-of-mass energy of about 100 TeV.
A Toolkit of the Stop Search via the Chargino Decay
Yang Bai,Hsin-Chia Cheng,Jason Gallicchio,Jiayin Gu
Physics , 2013, DOI: 10.1007/JHEP08(2013)085
Abstract: The top squark (stop) may dominantly decay to a bottom quark and a chargino if the mass difference between the stop and the lightest neutralino is comparable or less than the top quark mass. Such a moderately compressed spectrum is a challenging scenario for the stop search at the Large Hadron Collider, because it is difficult to separate the signals from the top and anti-top background. In this paper we focus on the di-leptonic decay channel, and consider many kinematic variables as possible discriminators. These include several MT2 variables and new "compatible-masses" variables which fully utilize all kinematic information of the background. We use several sample spectra with different characteristics to study the efficiencies of these variables in distinguishing the signal from the background. The finding is that different combinations of variables or strategies should be used for different spectra to maximally enhance the signal significance and expand the reach of the stop search in this scenario. The new variables that we proposed in this paper are also useful for other new physics searches with di-leptonic top and anti-top events as the dominant background.
The Zbb Couplings at Future e+e- Colliders
Stefania Gori,Jiayin Gu,Lian-Tao Wang
Physics , 2015,
Abstract: Many new physics models predict sizable modifications to the SM Zbb couplings, while the corresponding measurements at LEP and SLC exhibit some discrepancy with the SM predictions. After updating the current results on the Zbb coupling constraints from global fits, we list the observables that are most important for improving the Zbb coupling constraints and estimate the expected precision reach of three proposed future e+e- colliders, CEPC, ILC and FCC-ee. We consider both the case that the results are SM-like and the one that the Zbb couplings deviate significantly from the SM predictions. We show that, if we assume the value of the Zbb couplings to be within 68% CL of the current measurements, any one of the three colliders will be able to rule out the SM with more than 99.9999% CL (5 sigma). We study the implications of the improved Zbb coupling constraints on new physics models, and point out their complementarity with the constraints from the direct search of new physics particles at the LHC, as well as with Higgs precision measurements. Our results provide a further motivation for the construction of future e+e- colliders.
New Measures of Chinese University Library Knowledge Service under the Cloudization Background  [PDF]
Jiayin Liu, Chen Chen
Intelligent Information Management (IIM) , 2018, DOI: 10.4236/iim.2018.103006
Abstract: This article mainly explores and analyzes the application of network broadcast in the lecture service of university library under the cloudization background. By using the online survey method to investigate the lectures in some universities, it introduces the classification and characteristics of the network broadcast and obtains the advantage of network broadcast applied to lecture training through making contrast between the means of network multimedia. The result shows that the introduction of network broadcast can realize more customized, virtual and specialized lecture services, and facilitate the transformation of university library services in the digital era.
Page 1 /8893
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.