118654448
Constraints on the universal varying Yukawa couplings: from SM-like to fermiophobic
A bstractVarying the Standard Model (SM) fermion Yukawa couplings universally by a generic positive scale factor $ ({F_{{Y\,u}}}) $, we study the phenomenological fit to the current available experimental results for the Higgs boson search at hadron colliders. We point out that the Higgs production cross section and its decay branching ratio to γγ can be varied oppositely by $ {F_{{Y{ ~ }u}}} $ to make their product almost invariant. Thus, our scenario and the SM Higgs are indistinguishable in the inclusive H → γγ channel. The current measurements on direct Yukawa coupling strength in the $ H \to b\overline b /\tau \tau $ channel are not precise enough to fix the scale factor $ {F_{{Y{ ~ }u}}} $. The most promising is the vector-boson-fusion channel in which the CMS has already observed possible suppression effect on the Yukawa couplings. Further more, the global χ2 fit of the experimental data can get the optimal value by introducing a suppression factor $ {F_{{Y{ ~ }u}}} \sim {1}/{2} $ on the SM Yukawa couplings.
118887313
$\mathscr{O}(100 GeV)$ Deci-weak $W^\prime/Z^\prime$ at Tevatron and LHC
Recently Tevatron released their measurements on invariant mass spectrum of electron/positron, as well as the di-jet arising from WW+WZ production with one W leptonically decay. Though the statistics is not significant, there are two bumps around 240 GeV and 120-160 GeV respectively. We proposed that the two bumps correspond to the extra light gauge bosons $Z^\prime$ and $W^\prime$, which couple with quarks with the deci-weak strength. In this brief report, we also simulated di-jet invariant mass distribution at the current running LHC.
119241558
Distinguishing the Color Octet Axial-Vector-like Particle for Top Quark Asymmetry via Color Flow Method at the LHC
Tianjun Li Xia Wan You-kai Wang , and Shou-hua Zhu 1 State Key Laboratory of Theoretical Physics and Kavli Institute for Theoretical Physics China (KITPC), Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China 3 Institute of Theoretical Physics & State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China 4 Center for High Energy Physics, Peking University, Beijing 100871, China (Dated: May 7, 2014)
117142150
New Color-Octet Vector Boson?
Both CDF and D0 at Tevatron reported the measurements of forward-backward asymmetry in top pair production, which showed possible deviation from the standard model QCD prediction. In this paper, we show that a new color-octet massive vector boson with mass just above twice that of top quark can simultaneously account for the asymmetry and differential distribution $d\sigma/dM_{t\bar t}$ in top pair production, without conflict with other measurements for example di-jet production. The new particle can be discovered and studied at the more powerful Large Hadron Collider.
119280152
New color-octet vector boson revisited
Motivated by CDF recent measurements on di-jet invariant mass spectrum where di-jet is associated production with charged leptons ($e/\mu$) and missing energy, we re-examine the previous proposed massive color-octet axial-vector-like boson $Z_c$. Our simulation showed that the di-jet bump around 120-160 GeV can be induced by $Z_c$ with effective coupling $g_{Z_c q \bar q} =0.2 g_s$ (q represents the quark other than top and $g_s$ is the strong coupling constant). Moreover our numerical investigation indicated that the top quark forward-backward asymmetry $A_{FB}^t$ can be reproduced without distorting shape of differential cross section $d\sigma/d M_{t\bar t}$, provided that the $Z_c$ and top quark coupling is appropriately chosen ($g_{Z_c t \bar t} \simeq 4.5 g_{Z_c q \bar q}$). Our results also showed that the theoretical $A_{FB}^t$ as functions of $\Delta y$ and $M_{t\bar t}$ can be consistent with data within $1\sigma$ and $1.8\sigma$ respectively.
121528240
Study of the data taking strategy for a high precision τ mass measurement
To achieve a high precision τ mass measurement at the high luminosity experiment BESIII, Monte Carlo simulation and sampling technique are utilized to simulate various data taking cases for single and multi-parameter fits by virtue of which the optimal scheme is determined. The optimized proportion of luminosity distributed at selected points and the relation between precision and luminosity are obtained. In addition, the optimization of the fit scheme is confirmed by scrutinizing a variety of fit possibilities.
17457342
Curvaton dynamics and the non-linearity parameters in the curvaton model
We investigate the curvaton dynamics and the non-linearity parameters in the curvaton model with a potential slightly deviating from the quadratic form in detail. The non-linearity parameter gNL will show up due to the curvaton self-interaction. We also point out that the leading order of the non-quadratic term in the curvaton potential can be negative, for example in the axion-type curvaton model. If a large positive gNL is detected, the axion-type curvaton model will be preferred.
119871313
The BESIII muon identification system
The muon identification system of BESIII experiment at the IHEP is described. The muon counter (MUC) is composed of resistive plate chambers (RPCs) working in self-quenching streamer mode with the gas mixture Ar/C(2)F(4)H(2)/C(4)H(10)=50/42/8. The design, the construction, the mass production and the quality control result of the detectors are described in detail. The paper also presents the performance of the bare RPCs and the superlayer modules with cosmic rays. Finally, the subsystems of MUC, including the RPC superlayer modules, the gas systems, the HV and LV system and the readout electronic system, are also presented. (C) 2009 Elsevier B.V. All rights reserved.
119283904
CMB cold spot from inflationary feature scattering
Abstract We propose a “feature-scattering” mechanism to explain the cosmic microwave background cold spot seen from WMAP and Planck maps. If there are hidden features in the potential of multi-field inflation, the inflationary trajectory can be scattered by such features. The scattering is controlled by the amount of isocurvature fluctuations, and thus can be considered as a mechanism to convert isocurvature fluctuations into curvature fluctuations. This mechanism predicts localized cold spots (instead of hot ones) on the CMB. In addition, it may also bridge a connection between the cold spot and a dip on the CMB power spectrum at l ∼ 20 .
119976206
Current progress of nuclear astrophysical reaction and decay study at CIAE
Presented here was current progress of the study of nuclear astrophysical reaction and decay at CIAE. We studied astrophysical 12N(p,γ)13O reaction through the measurement of the 12N(d,n)13O angular distribution in inverse kinematics. Our result is in agreement with that from the 14N(12N,13O)13C reaction and two shell model calculations. We also measured the angular distributions of single neutron transfer reaction of 7Li(6Li,7Li)6Li, and derived the reaction cross section for 6Li(n,γ)7Li by using the present spectroscopic factor. The astrophysical reaction rate is found to be higher by a factor of 1.7 than the value adopted in previous reaction network calculations. In addition, half-life of 147Sm in metal samarium and Sm2O3 was measured. No significant change has been observed within the experimental uncertainty.
119253997
Constraints on flavor-changing neutral-current $Htq$ couplings from the signal of $tH$ associated production with QCD next-to-leading order accuracy at the LHC
We study a generic Higgs boson and a top quark associated production via model-independent flavor-changing neutral-current couplings at the LHC, including complete QCD next-to-leading order (NLO) corrections to the production and decay of the top quark and the Higgs boson. We find that QCD NLO corrections can increase the total production cross sections by about 48.9% and 57.9% for the Htu and Htc coupling induced processes at the LHC, respectively. After kinematic cuts are imposed on the decay products of the top quark and the Higgs boson, the QCD NLO corrections are reduced to 11% for the Htu coupling induced process and almost vanish for the Htc coupling induced process. Moreover, QCD NLO corrections reduce the dependence of the total cross sections on the renormalization and factorization scales. We also discuss signals of the