Neutral Kaon Mixing from Lattice QCD

In this work, we report the lattice calculation of two important quantities which emerge from second order, K0 − ¯ K0 mixing : ∆MK and K. The RBC-UKQCD collaboration has performed the first calculation of ∆MK with unphysical kinematics [1]. We now extend this calculation to near-physical and physical ensembles. In these physical or near-physical calculations, the two-pion energies are below the kaon threshold, and we have to examine the two-pion intermediate states contribution to ∆MK, as well as the enhanced finite volume corrections arising from these two-pion intermediate states. We also report the first lattice calculation of the long-distance contribution to the indirect CP violation parameter, the K. This calculation involves the treatment of a short-distance, ultra-violet divergence that is absent in the calculation of ∆MK, and we will report our techniques for correcting this divergence on the lattice. In this calculation, we used unphysical quark masses on the same ensemble that we used in [1]. Therefore, rather than providing a physical result, this calculation demonstrates the technique for calculating K, and provides an approximate understanding the size of the long-distance contributions. Various new techniques are employed in this work, such as the use of All-Mode-Averaging (AMA), the All-to-All (A2A) propagators and the use of super-jackknife method in analyzing the data

Long-distance contribution to ϵK\epsilon_K from lattice QCD

A lattice QCD approach to the calculation of the long-distance contributions to $\epsilon_K$ is presented. This parameter describes indirect CP violation in $K\to\pi\pi$ decay. While the short-distance contribution to $\epsilon_K$ can be accurately calculated in terms of standard model parameters and a single hadronic matrix element, $B_K$, there is a long-distance part which is estimated to be approximately $5\%$ of the total and is more difficult to determine. A method for determining this small but phenomenologically important contribution to $\epsilon_K$ using lattice QCD is proposed and a complete exploratory calculation of the contribution is presented. This exploratory calculation uses an unphysical light quark mass corresponding to a 339 MeV pion mass and an unphysical charm quark mass of 968 MeV, expressed in the $\overline{\mathrm{MS}}$ scheme at 2 GeV. This calculation demonstrates that future work should be able to determine this long-distance contribution from first principles with a controlled error of 10\% or less

Exploratory lattice QCD study of the rare kaon decay K+→π+ννˉK^+\to\pi^+\nu\bar{\nu}

In Ref [1] we have presented the results of an exploratory lattice QCD computation of the long-distance contribution to the $K^+\to\pi^+\nu\bar{\nu}$ decay amplitude. In the present paper we describe the details of this calculation, which includes the implementation of a number of novel techniques. The $K^+\to\pi^+\nu\bar{\nu}$ decay amplitude is dominated by short-distance contributions which can be computed in perturbation theory with the only required non-perturbative input being the relatively well-known form factors of semileptonic kaon decays. The long-distance contributions, which are the target of this work, are expected to be of O(5%) in the branching ratio. Our study demonstrates the feasibility of lattice QCD computations of the $K^+\to\pi^+\nu\bar{\nu}$ decay amplitude, and in particular of the long-distance component. Though this calculation is performed on a small lattice ($16^3\times32$) and at unphysical pion, kaon and charm quark masses, $m_\pi=420$ MeV, $m_K=563$ MeV and m_c^{\overline{\mathrm{MS}}}(\mbox{2 GeV})=863 MeV, the techniques presented in this work can readily be applied to a future realistic calculation.Comment: 74 pages, 12 figure

Exploratory Lattice QCD Study of the Rare Kaon Decay K+→π+ν ν ¯

We report a first, complete lattice QCD calculation of the long-distance contribution to the $K^+\to\pi^+\nu\bar{\nu}$ decay within the standard model. This is a second-order weak process involving two four-Fermi operators that is highly sensitive to new physics and being studied by the NA62 experiment at CERN. While much of this decay comes from perturbative, short-distance physics there is a long-distance part, perhaps as large as the planned experimental error, which involves nonperturbative phenomena. The calculation presented here, with unphysical quark masses, demonstrates that this contribution can be computed using lattice methods by overcoming three technical difficulties: (i) a short-distance divergence that results when the two weak operators approach each other, (ii) exponentially growing, unphysical terms that appear in Euclidean, second-order perturbation theory, and (iii) potentially large finite-volume effects. A follow-on calculation with physical quark masses and controlled systematic errors will be possible with the next generation of computers.Comment: 5 pages, 2 figures, 1 table; v2, version accepted for publication in PR

HPRT Mutations in Lymphocytes from 1,3-Butadiene-Exposed Workers in China

BACKGROUND: 1,3-Butadiene (BD) is an important industrial chemical and an environmental and occupational pollutant. The carcinogenicity of BD in rodents has been proved, but its carcinogenic and mutagenic molecular mechanism(s) are not fully elucidated in humans. OBJECTIVES: In the present study, we compared the mutation frequencies and exon deletions of BD-exposed workers with that of control subjects in China to identify the characteristic mutations associated with BD exposure in the human HPRT (hypoxanthine–guanine–phosphoribosyltransferase) gene. METHODS: Seventy-four workers exposed to BD via inhalation and 157 matched controls were evaluated in Nanjing, China. Molecular analysis of HPRT mutant T lymphocytes from BDexposed workers and nonexposed control subjects was conducted to identify changes in the structure of the HPRT gene. A total of 783 HPRT mutants were analyzed by multiplex polymerase chain reaction, in which 368 HPRT mutants were isolated from BD-exposed workers and 415 mutants from control subjects. RESULTS: The BD-exposed workers showed a higher mutation frequency (18.2 ± 9.4 × 10 –6) than the control subjects (12.7 ± 7.3 × 10 –6), but the difference was not significant (p> 0.05). The frequency of exon deletions in BD-exposed workers (27.4%) was significantly higher than that in control subjects (12.5%) (p < 0.05), which mainly included multiplex exon deletions (2–8 exons). CONCLUSIONS: The results of the present study suggest that BD should increase the frequency of large deletions of HPRT gene in human lymphocytes This change confirms and supports the previous findings in BD-exposed workers. KEY WORDS: 1,3-butadiene, BD, exon deletion, HPRT gene, lymphocyte, occupational exposure. Environ Health Perspect 116:203–208 (2008). doi:10.1289/ehp.10353 available vi

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

The Australian and New Zealand’s VAT Model on Financial Service Industry: an Introduction on Experience to China

In the current stage of China’s VAT Reform the proper model and tax rates that areapplicable to financial services are yet to be finalised. Unlike developed countries in Europe,Australia and New Zealand took different approaches in dealing with VAT issues in thefinancial industry. Their experience in implementing special VAT treatment of financialservices can provide an alternative and informative perspective into the conundrum that theChinese government is facing. This paper introduces the VAT laws and regulations of Australiaand New Zealand and compares the effectiveness of the two different models. In considerationof China’s special realities, it endeavours to make a series of practical suggestions for theforthcoming VAT laws and regulations regarding the financial sector

The K_L - K_S mass difference

We review the status of the RBC-UKQCD collaborations' computations of the KL-KS mass difference. After a brief discussion of the theoretical framework which had been developed previously by the collaboration, we describe our latest computation, performed at physical quark masses, and present our preliminary result mKL - mKS = (5.5 ± 1.70) × 10-12 MeV.</p

The KL - KS Mass Difference

We review the status of the RBC-UKQCD collaborations’ computations of the KL-KS mass difference. After a brief discussion of the theoretical framework which had been developed previously by the collaboration, we describe our latest computation, performed at physical quark masses, and present our preliminary result mKL - mKS = (5.5 ± 1.70) × 10-12 MeV