ITP OpenIR研究单元&专题: SCI论文
http://ir.itp.ac.cn/:80/handle/311006/211
Mon, 25 Mar 2019 20:51:18 GMT2019-03-25T20:51:18ZX (4260) revisited: A coupled channel perspective
http://ir.itp.ac.cn/:80/handle/311006/23011
题名: X (4260) revisited: A coupled channel perspective
作者: Lu, Y; Anwar, MN; Zou, BS
摘要: We calculate the probabilities of various charmed meson molecules for X (4260) under the framework of the P-3(0) model. The results indicate that, even though heavy quark spin symmetry forbids S wave coupling of D-1(D) over bar to the S-3(1) charmonia [psi(nS)], the D wave coupling is allowed and not negligible. Under this symmetry, the D-1(D) over bar can couple to D-3(1) charmonia [psi(nD)] via both S and D waves, and the overall coupling is around three times larger than that of psi(nS). The X (4260) cannot be a pure molecule but a mixture of a charmonium and various charmed meson components. Since the D-1(D) over bar couples strongly to psi(nD), our results suggest that, in the D-1(D) over bar molecular picture, the charmonium core of X (4260) is psi(nD) instead of psi(nS). As a result, the experimental fact that the R ratio has a dip around 4.26 GeV can be understood in the D-1(D) over bar molecular picture of the X (4260).Fri, 28 Dec 2018 02:58:56 GMThttp://ir.itp.ac.cn/:80/handle/311006/230112018-12-28T02:58:56ZLarge number limit of multifield inflation
http://ir.itp.ac.cn/:80/handle/311006/23012
题名: Large number limit of multifield inflation
作者: Guo, ZK
摘要: We compute the tensor and scalar spectral index n(t), n(s), the tensor-to-scalar ratio r, and the consistency relation n(t)/r in the general monomial multifield slow-roll inflation models with potentials V similar to Sigma(i)lambda(i)vertical bar phi(i)vertical bar(Pi). The general models give a novel relation that nt, ns and n(t)/r are all proportional to the logarithm of the number of fields N-f when N-f is getting extremely large with the order of magnitude around O(10(40)) thorn. An upper bound N-f less than or similar to N*e(ZN)* is given by requiring the slow variation parameter small enough where N-* is the e-folding number and Z is a function of distributions of lambda(i) and rho(i). Besides, n(t)/r differs from the single-field result - 1/8 with substantial probability except for a few very special cases. Finally, we derive theoretical boundsr r > 2/N-* (r greater than or similar to 0.03) and for nt, which can be tested by observation in the near future.Fri, 28 Dec 2018 02:58:56 GMThttp://ir.itp.ac.cn/:80/handle/311006/230122018-12-28T02:58:56ZNote on the initial conditions within the effective field theory approach of cosmic acceleration
http://ir.itp.ac.cn/:80/handle/311006/23009
题名: Note on the initial conditions within the effective field theory approach of cosmic acceleration
作者: Liu, XW; Hu, B; Zhang, Y
摘要: By using the effective field theory approach, we investigate the role of initial conditions for the dark energy or modified gravity models. In detail, we consider the constant and linear parametrization of the effective Newton constant models. First, under the adiabatic assumption, the correction from the extra scalar degree of freedom in the beyond Lambda CDM model is found to be negligible. The dominant ingredient in this setup is the primordial curvature perturbation originated from the inflation mechanism, and the energy budget of the matter components is not very crucial. Second, the isocurvature perturbation sourced by the extra scalar field is studied. For the constant and linear models of the effective Newton constant, no such kind of scalar mode exists. For the quadratic model, there is a nontrivial one. However, the amplitude of the scalar field is damped away very fast on all scales. Consequently, it could not support a reasonable structure formation. Finally, we study the importance of the setup of the scalar field starting time. By setting different turn-on times, namely, a = 10(-2) and a = 10(-7), we compare the cosmic microwave background radiation temperature, lensing deflection angle autocorrelation function, and the matter power spectrum in the constant and linear models. We find there is an order of O(1%) thorn difference in the observable spectra for constant model, while for the linear model, it is smaller than O(0.1%).Fri, 28 Dec 2018 02:58:55 GMThttp://ir.itp.ac.cn/:80/handle/311006/230092018-12-28T02:58:55ZHigher order derivative coupling to gravity and its cosmological implications
http://ir.itp.ac.cn/:80/handle/311006/23010
题名: Higher order derivative coupling to gravity and its cosmological implications
作者: Cai, Y; Piao, YS
摘要: We show that the R-(3)delta K operator in effective field theory is significant for avoiding the instability of nonsingular bounce, where R-(3) and K-mu nu are the three-dimensional Ricci scalar and the extrinsic curvature on the spacelike hypersurface, respectively. We point out that the covariant Lagrangian of R-(3)delta K, i.e., L-R(3)delta K, has the second order derivative couplings of scalar field to gravity which do not appear in Horndeski theory or its extensions but does not bring the Ostrogradski ghost. We also discuss the possible effect of L-R(3)delta K on the primordial scalar perturbation in the inflation scenario.Fri, 28 Dec 2018 02:58:55 GMThttp://ir.itp.ac.cn/:80/handle/311006/230102018-12-28T02:58:55ZLepton-flavored electroweak baryogenesis
http://ir.itp.ac.cn/:80/handle/311006/23008
题名: Lepton-flavored electroweak baryogenesis
作者: Guo, HK; Li, YY; Liu, T; Ramsey-Musolf, M; Shu, J
摘要: We explore lepton-flavored electroweak baryogenesis, driven by CP-violation in leptonic Yukawa sector, using the tau - mu system in the two Higgs doublet model as an example. This setup generically yields, together with the flavor-changing decay h -> tau mu, a tree-level Jarlskog invariant that can drive dynamical generation of baryon asymmetry during a first-order electroweak phase transition and results in CP-violating effects in the decay h -> tau tau. We find that the observed baryon asymmetry can be generated in parameter space compatible with current experimental results for the decays h -> tau mu, h -> tau tau, and tau -> mu gamma, as well as the present bound on the electric dipole moment of the electron. The baryon asymmetry generated is intrinsically correlated with the CP-violating decay h -> tau tau and the flavor-changing decay h -> tau mu, which thus may serve as "smoking guns" to test lepton-flavored electroweak baryogenesis.Fri, 28 Dec 2018 02:58:54 GMThttp://ir.itp.ac.cn/:80/handle/311006/230082018-12-28T02:58:54ZLearning from Higgs physics at future Higgs factories
http://ir.itp.ac.cn/:80/handle/311006/23007
题名: Learning from Higgs physics at future Higgs factories
作者: Gu, JY; Li, HL; Liu, Z; Su, SF; Su, W
摘要: Future Higgs factories can reach impressive precision on Higgs property measurements. In this paper, instead of conventional focus of Higgs precision in certain interaction bases, we explore its sensitivity to new physics models at the electron-positron colliders. In particular, we study two categories of new physics models, Standard Model (SM) with a real scalar singlet extension, and Two Higgs Double Model (2HDM) as examples of weakly-interacting models, Minimal Composite Higgs Model (MCHM) and three typical patterns of the more general operator counting for strong interacting models as examples of strong dynamics. We perform a global fit to various Higgs search channels to obtain the 95% C.L. constraints on the model parameter space. In the SM with a singlet extension, we obtain the limits on the singlet-doublet mixing angle sin theta, as well as the more general Wilson coefficients of the induced higher dimensional operators. In the 2HDM, we analyze tree level effects in tan beta vs. cos(beta-alpha) plane, as well as the one-loop contributions from the heavy Higgs bosons in the alignment limit to obtain the constraints on heavy Higgs masses for different types of 2HDM. In strong dynamics models, we obtain lower limits on the strong dynamics scale. In addition, once deviations of Higgs couplings are observed, they can be used to distinguish different models. We also compare the sensitivity of various future Higgs factories, namely Circular Electron Positron Collider (CEPC), Future Circular Collider (FCC)-ee and International Linear Collider (ILC).Fri, 28 Dec 2018 02:58:54 GMThttp://ir.itp.ac.cn/:80/handle/311006/230072018-12-28T02:58:54ZStatus and prospects of light bino-higgsino dark matter in natural SUSY
http://ir.itp.ac.cn/:80/handle/311006/23006
题名: Status and prospects of light bino-higgsino dark matter in natural SUSY
作者: Abdughani, M; Wu, L; Yang, JM
摘要: Given the recent progress in dark matter direction detection experiments, weexamine a light bino-higgsino dark matter (DM) scenario (M-1 < 100 GeV and mu < 300 GeV) in natural supersymmetry with the electroweak fine tuning measure Delta(EW) < 30. By imposing various constraints, we note that: (i) For sign(mu/M-1) = +1, the parameter space allowed by the DM relic density and collider bounds can almost be excluded by the very recent spin-independent (SI) scattering cross-section limits from the XENON1T (2017) experiment. (ii) For sign(mu/M-1) = -1, the SI limits can be evaded due to the cancelation effects in the h<(chi)over bar>(0)(1)(chi) over bar (0)(1) coupling, while rather stringent constraints come from the PandaX-II (2016) spin-dependent (SD) scattering cross-section limits, which can exclude the higgsino mass vertical bar mu vertical bar and the LSP mass m (chi) over bar (0)(1) up to about 230 and 37 GeV, respectively. Furthermore, the surviving parameter space will be fully covered by the projected XENON1T experiment or the future trilepton searches at the HL-LHC.Fri, 28 Dec 2018 02:58:53 GMThttp://ir.itp.ac.cn/:80/handle/311006/230062018-12-28T02:58:53ZX (4260) revisited: A coupled channel perspective
http://ir.itp.ac.cn/:80/handle/311006/22994
题名: X (4260) revisited: A coupled channel perspective
作者: Lu, Y; Anwar, MN; Zou, BS
摘要: We calculate the probabilities of various charmed meson molecules for X (4260) under the framework of the P-3(0) model. The results indicate that, even though heavy quark spin symmetry forbids S wave coupling of D-1(D) over bar to the S-3(1) charmonia [psi(nS)], the D wave coupling is allowed and not negligible. Under this symmetry, the D-1(D) over bar can couple to D-3(1) charmonia [psi(nD)] via both S and D waves, and the overall coupling is around three times larger than that of psi(nS). The X (4260) cannot be a pure molecule but a mixture of a charmonium and various charmed meson components. Since the D-1(D) over bar couples strongly to psi(nD), our results suggest that, in the D-1(D) over bar molecular picture, the charmonium core of X (4260) is psi(nD) instead of psi(nS). As a result, the experimental fact that the R ratio has a dip around 4.26 GeV can be understood in the D-1(D) over bar molecular picture of the X (4260).Thu, 27 Dec 2018 07:51:20 GMThttp://ir.itp.ac.cn/:80/handle/311006/229942018-12-27T07:51:20ZLarge number limit of multifield inflation
http://ir.itp.ac.cn/:80/handle/311006/22995
题名: Large number limit of multifield inflation
作者: Guo, ZK
摘要: We compute the tensor and scalar spectral index n(t), n(s), the tensor-to-scalar ratio r, and the consistency relation n(t)/r in the general monomial multifield slow-roll inflation models with potentials V similar to Sigma(i)lambda(i)vertical bar phi(i)vertical bar(Pi). The general models give a novel relation that nt, ns and n(t)/r are all proportional to the logarithm of the number of fields N-f when N-f is getting extremely large with the order of magnitude around O(10(40)) thorn. An upper bound N-f less than or similar to N*e(ZN)* is given by requiring the slow variation parameter small enough where N-* is the e-folding number and Z is a function of distributions of lambda(i) and rho(i). Besides, n(t)/r differs from the single-field result - 1/8 with substantial probability except for a few very special cases. Finally, we derive theoretical boundsr r > 2/N-* (r greater than or similar to 0.03) and for nt, which can be tested by observation in the near future.Thu, 27 Dec 2018 07:51:20 GMThttp://ir.itp.ac.cn/:80/handle/311006/229952018-12-27T07:51:20ZNote on the initial conditions within the effective field theory approach of cosmic acceleration
http://ir.itp.ac.cn/:80/handle/311006/22992
题名: Note on the initial conditions within the effective field theory approach of cosmic acceleration
作者: Liu, XW; Hu, B; Zhang, Y
摘要: By using the effective field theory approach, we investigate the role of initial conditions for the dark energy or modified gravity models. In detail, we consider the constant and linear parametrization of the effective Newton constant models. First, under the adiabatic assumption, the correction from the extra scalar degree of freedom in the beyond Lambda CDM model is found to be negligible. The dominant ingredient in this setup is the primordial curvature perturbation originated from the inflation mechanism, and the energy budget of the matter components is not very crucial. Second, the isocurvature perturbation sourced by the extra scalar field is studied. For the constant and linear models of the effective Newton constant, no such kind of scalar mode exists. For the quadratic model, there is a nontrivial one. However, the amplitude of the scalar field is damped away very fast on all scales. Consequently, it could not support a reasonable structure formation. Finally, we study the importance of the setup of the scalar field starting time. By setting different turn-on times, namely, a = 10(-2) and a = 10(-7), we compare the cosmic microwave background radiation temperature, lensing deflection angle autocorrelation function, and the matter power spectrum in the constant and linear models. We find there is an order of O(1%) thorn difference in the observable spectra for constant model, while for the linear model, it is smaller than O(0.1%).Thu, 27 Dec 2018 07:51:19 GMThttp://ir.itp.ac.cn/:80/handle/311006/229922018-12-27T07:51:19Z