A Lattice Study of (Dˉ1D∗)±(\bar{D}_1 D^{*})^\pm Near-threshold Scattering

In this exploratory lattice study, low-energy near threshold scattering of the $(\bar{D}_1 D^{*})^\pm$ meson system is analyzed using lattice QCD with $N_f=2$ twisted mass fermion configurations. Both s-wave ($J^P=0^-$) and p-wave ($J^P=1^+$) channels are investigated. It is found that the interaction between the two charmed mesons is attractive near the threshold in both channels. This calculation provides some hints in the searching of resonances or bound states around the threshold of $(\bar{D}_1 D^{*})^\pm$ system.Comment: 20 pages, 15 figures, matches the version on PR

Non-perturbative renormalization of overlap quark bilinears on 2+1-flavor domain wall fermion configurations

We present renormalization constants of overlap quark bilinear operators on 2+1-flavor domain wall fermion configurations. This setup is being used by the chiQCD collaboration in calculations of physical quantities such as strangeness in the nucleon and the strange and charm quark masses. The scale independent renormalization constant for the axial vector current is computed using the Ward Identity. The renormalization constants for scalar, pseudoscalar and vector current are calculated in the RI-MOM scheme. Results in the MS-bar scheme are also given. The step scaling function of quark masses in the RI-MOM scheme is computed as well. The analysis uses, in total, six different ensembles of three sea quarks each on two lattices with sizes 24^3x64 and 32^3x64 at spacings a=(1.73 GeV)^{-1} and (2.28 GeV)^{-1}, respectively.Comment: 26 pages, 17 figures. More discussions on O(4) breaking effects, and on the perturbative running and a^2p^2 extrapolation of Zs. A subsection for the calculation of the step scaling function of quark mass is added. References added. Version to appear in PR

A way to measure the water quality of the LHAASO-WCDA with cosmic muon signals

The Large High Altitude Air Shower Observatory (LHAASO) is to be built at Daocheng, Sichuan Province, China. As one of the major components of the LHAASO project, a Water Cherenkov Detector Array (WCDA), with an area of 78,000~$\rm m^{2}$, contains 350,000~tons of purified water. The water transparency and its stability are critical for successful long-term operation of this project. To gain full knowledge of the water Cherenkov technique and investigate the engineering issues, a 9-cell detector array has been built at the Yangbajing site, Tibet, China. With the help of the distribution of single cosmic muon signals, the monitoring and measurement of water transparency are studied. The results show that a precision of several percent can be obtained for the attenuation length measurement, which satisfies the requirements of the experiment. In the near future, this method could be applied to the LHAASO-WCDA project

Two Photon Decays of ηc\eta_c from Lattice QCD

We present an exploratory lattice study for the two-photon decay of $\eta_c$ using $N_f=2$ twisted mass lattice QCD gauge configurations generated by the European Twisted Mass Collaboration. Two different lattice spacings of $a=0.067$fm and $a=0.085$fm are used in the study, both of which are of physical size of 2$fm$. The decay widths are found to be $1.025(5)$KeV for the coarser lattice and $1.062(5)$KeV for the finer lattice respectively where the errors are purely statistical. A naive extrapolation towards the continuum limit yields $\Gamma\simeq 1.122(14)$KeV which is smaller than the previous quenched result and most of the current experimental results. Possible reasons are discussed.Comment: 13 pages, 7 figures; matches the published versio

Coherency in Neutrino-Nucleus Elastic Scattering

Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter ($\alpha$) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold and target nucleus are studied. The ranges of $\alpha$ which can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in $\alpha$ would constrain sensitivities in probing physics beyond the standard model. The maximum neutrino energies corresponding to $\alpha$>0.95 are derived.Comment: 5 pages, 4 figures, 3 tables. V2 -- Published Versio

Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. V. A New Size-Luminosity Scaling Relation for the Broad-Line Region

This paper reports results of the third-year campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs) between 2014-2015. Ten new targets were selected from quasar sample of Sloan Digital Sky Survey (SDSS), which are generally more luminous than the SEAMBH candidates in last two years. H$\beta$ lags ($\tau_{_{\rm H\beta}}$) in five of the 10 quasars have been successfully measured in this monitoring season. We find that the lags are generally shorter, by large factors, than those of objects with same optical luminosity, in light of the well-known $R_{_{\rm H\beta}}-L_{5100}$ relation. The five quasars have dimensionless accretion rates of $\dot{\mathscr{M}}=10-10^3$. Combining measurements of the previous SEAMBHs, we find that the reduction of H$\beta$ lags tightly depends on accretion rates, $\tau_{_{\rm H\beta}}/\tau_{_{R-L}}\propto\dot{\mathscr{M}}^{-0.42}$, where $\tau_{_{R-L}}$ is the H$\beta$ lag from the normal $R_{_{\rm H\beta}}-L_{5100}$ relation. Fitting 63 mapped AGNs, we present a new scaling relation for the broad-line region: $R_{_{\rm H\beta}}=\alpha_1\ell_{44}^{\beta_1}\,\min\left[1,\left(\dot{\mathscr{M}}/\dot{\mathscr{M}}_c\right)^{-\gamma_1}\right]$, where $\ell_{44}=L_{5100}/10^{44}\,\rm erg~s^{-1}$ is 5100 \AA\ continuum luminosity, and coefficients of $\alpha_1=(29.6_{-2.8}^{+2.7})$ lt-d, $\beta_1=0.56_{-0.03}^{+0.03}$, $\gamma_1=0.52_{-0.16}^{+0.33}$ and $\dot{\mathscr{M}}_c=11.19_{-6.22}^{+2.29}$. This relation is applicable to AGNs over a wide range of accretion rates, from $10^{-3}$ to $10^3$. Implications of this new relation are briefly discussed.Comment: 15 pages, 9 figures, 5 table, accepted for publication in The Astrophysical Journa

Limits on light WIMPs from the CDEX-1 experiment with a p-type point-contact germanium detector at the China Jingping Underground Laboratory

We report results of a search for light Dark Matter WIMPs with CDEX-1 experiment at the China Jinping Underground Laboratory, based on 53.9 kg-days of data from a p-type point-contact germanium detector enclosed by a NaI(Tl) crystal scintillator as anti-Compton detector. The event rate and spectrum above the analysis threshold of 475 eVee are consistent with the understood background model. Part of the allowed regions for WIMP-nucleus coherent elastic scattering at WIMP mass of 6-20 GeV are probed and excluded. Independent of interaction channels, this result contradicts the interpretation that the anomalous excesses of the CoGeNT experiment are induced by Dark Matter, since identical detector techniques are used in both experiments.Comment: 5 pages, 5 figure

Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg ×{\times} day Data of the CDEX-10 Experiment

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8 $\times 10^{-42}$ and 3 $\times 10^{-36}$ cm$^{2}$ at a 90\% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass ($m_{\chi}$) of 5 GeV/${c}^2$ are achieved. The lower reach of $m_{\chi}$ is extended to 2 GeV/${c}^2$.Comment: 5 pages, 4 figure

A Unified Approach to the Classical Statistical Analysis of Small Signals

We give a classical confidence belt construction which unifies the treatment of upper confidence limits for null results and two-sided confidence intervals for non-null results. The unified treatment solves a problem (apparently not previously recognized) that the choice of upper limit or two-sided intervals leads to intervals which are not confidence intervals if the choice is based on the data. We apply the construction to two related problems which have recently been a battle-ground between classical and Bayesian statistics: Poisson processes with background, and Gaussian errors with a bounded physical region. In contrast with the usual classical construction for upper limits, our construction avoids unphysical confidence intervals. In contrast with some popular Bayesian intervals, our intervals eliminate conservatism (frequentist coverage greater than the stated confidence) in the Gaussian case and reduce it to a level dictated by discreteness in the Poisson case. We generalize the method in order to apply it to analysis of experiments searching for neutrino oscillations. We show that this technique both gives correct coverage and is powerful, while other classical techniques that have been used by neutrino oscillation search experiments fail one or both of these criteria.Comment: 40 pages, 15 figures. Changes 15-Dec-99 to agree more closely with published version. A few small changes, plus the two substantive changes we made in proof back in 1998: 1) The definition of "sensitivity" in Sec. V(C). It was inconsistent with our actual definition in Sec. VI. 2) "Note added in proof" at end of the Conclusio

Dysglycemia but not lipids is associated with abnormal urinary albumin excretion in diabetic kidney disease: a report from the Kidney Early Evaluation Program (KEEP)

BACKGROUND: The relationship between glycemic control and lipid abnormalities with urinary albumin-creatinine ratio (ACR) in chronic kidney disease (CKD) patients with diabetes mellitus (DM) is unknown. We sought to investigate the association of dyslipidemia and glycemic control with levels of albuminuria in the National Kidney Foundation (NKF) Kidney Early Evaluation Program (KEEP) participants with DM and CKD stage 3 or higher. METHODS: We performed a cross-sectional study of 6639 eligible KEEP patients with DM and CKD Stage 3 to 5 from June 2008 to December 2009. Multivariate logistic regression was used to evaluate the association of lipid parameters (per 10 mg/dl change in serum level) and glycosylated hemoglobin (HbA1c) values with three degrees of albuminuria normo (<30 mg⁄g), micro (30 to 300 mg⁄g) and macro (>300 mg⁄g). RESULTS: 2141 KEEP participants were included. HbA1c levels were strongly associated with micro-albuminuria (compared to normo-albuminuria) and macro-albuminuria (compared to normo-albuminuria and micro-albuminuria). Each 1.0% increase in HbA1c increased the odds of micro-albuminuria by 32% (OR 1.32, 95% CI 1.23-1.42) and the odds of macro-albuminuria (vs. microalbuminuria) by 16% (OR 1.16, 95% CI 1.05-1.28). Only increases in serum HDL were associated with decreased odds of micro-albuminuria; otherwise, the association between other components of the serum lipid profile with urinary ACR did not reach statistical significance. CONCLUSION: In this cross-sectional study of 2141 KEEP participants with DM and CKD stages 3–5, overall glycemic control but not lipids were associated with abnormal urinary albumin excretion, a marker of increased risk for progressive disease