16179887
First calculation of cosmic-ray muon spallation backgrounds for MeV astrophysical neutrino signals in Super-Kamiokande
signals is much larger than the signal rates for kinetic energies of about 6 { 18 MeV. Surprisingly, there is no published calculation of the production and properties of these backgrounds in water, though there are such studies for scintillator. Using the simulation code FLUKA and theoretical insights, we detail how muons lose energy in water, produce secondary particles, how and where these secondaries produce isotopes, and the properties of the backgrounds from their decays. We reproduce Super-Kamiokande measurements of the total background to within a factor of 2, which is good given that the isotope yields vary by orders of magnitude and that some details of the experiment are unknown to us at this level. Our results break aggregate data into component isotopes, reveal their separate production mechanisms, and preserve correlations between them. We outline how to implement more eective background rejection techniques using this information. Reducing backgrounds in solar and DSNB studies by even a factor of a few could help lead to important new discoveries.
118377935
Similarity renormalization group with novel generators
The choice of generator in the Similarity Renormalization Group (SRG) flow equation determines the evolution pattern of the Hamiltonian. The kinetic energy has been used in the generator for most prior applications to nuclear interactions, and other options have been largely unexplored. Here we show how variations of this standard choice can allow the evolution to proceed more efficiently without losing its advantages.
118396850
SO(4) monopole as a new topological invariant and its topological structure
By making use of the decomposition theory of gauge potential, the inner structure of SU(2) and SO(4) gauge theory is discussed in detail. We find the SO(4) monopole can be given via projecting the SO(4) gauge field onto an antisymmetric tensor. This projection fix the coset $% SU(2)/U(1)\bigotimes SU(2)/U(1)$ of SO(4) gauge group. The generalized Hopf map is given via a Dirac spinor. Further we prove that this monopole can be consider as a new topological invariant. Which is composed of two monopole structures. Local topological structure of the SO(4) monopole is discussed in detail, which is quantized by winding number. The Hopf indices and Brouwer degree labels the local property of the monopoles.
118740978
Constraints on Randall-Sundrum model from the events of dijet production with QCD next-to-leading order accuracy at the LHC
We study the dijet production in Randall-Sundrum model at the LHC with QCD next-to-leading(NLO) order accuracy. Our results show that the QCD NLO corrections can increase the total cross sections by more than $80\%$ and reduce the scale dependence. We also explore in detail several important kinematic distributions at the NLO level. Moreover, we discuss the upper limits of the KK graviton excluded mass range and the allowed parameter space for the coupling constant and KK graviton mass, using the experiment data.
53510978
Threshold resummation for the production of a color sextet (antitriplet) scalar at the LHC
We investigate threshold resummation effects in the production of a color sextet (antitriplet) scalar at next-to-next-to-leading logarithmic (NNLL) order at the LHC in the frame of soft-collinear effective theory. We show the total cross section and the rapidity distribution with NLO+NNLL accuracy, and we compare them with the NLO results. Besides, we use recent dijet data at the LHC to give the constraints on the couplings between the colored scalars and quarks.
119531071
Comments on CLEO new measurements for $\upsilon_{1S}$ decays to charmonium final states and investigations on associate strange particle enhancement in $\upsilon$ to J/Psi + $X$
The recent measurements by CLEO Collaboration for the inclusive J/Psi and Psi(2S) production in Upsilon(1S) decay and our previous calculation are analyzed. The J/Psi momentum spectrum and the production ratio of Psi(2S) versus J/Psi favour Upsilon to J/Psi(Psi(2S)) + ccbar g as the dominant contribution. We point out that the differences between the experimental data and our previous results are mainly originated from the setting of the parameter charm quark mass. We further suggest the associate strange particle enhancement as a probe for the open charm particles in Upsilon to J/Psi (Psi(2S)) + ccbar g.
120721773
PRELIMINARY COMMISSIONING OF SUPERCONDUCTING MAGNETS AND CRYOGENIC SYSTEM OF BEPC II
A helium cryogenic system with cooling capacity of 1 kW at 4.5 K was set up at Institute of High Energy Physics, Chinese Academy of Sciences, Beijing. This helium refrigerating system is dedicated for the cooling of two superconducting radio frequency (SRF) cavities, two interaction region superconducting collision quadrupole (SCQ) magnets, a detector superconducting solenoid magnet (SSM), which are the key items of the upgrade project of Beijing Electron-Positron Collider (BEPC II). Commissioning with the detector and SCQ magnets was carried out, which will be introduced in this paper. The cryogenic system shows very robust as SSM quench. This paper presents the overall status and some test results of superconducting and cryogenic system.