118994414
Perturbative calculation of the excluded volume effect for nuclear matter in a relativistic mean-field approximation
Considering the finite volume of nucleons, a Lagrangian density is given. The first-order self-energy of the nucleon and the equation of state of nuclear matter are calculated in the framework of the relativistic mean-field approximation. Our results indicate that the effects of the volume of nucleons are not negligible.
117634870
Some properties of pi meson in nuclear matter with finite density
In the GCM we study some properties of pi meson as the Goldstone bosons in a nuclear matter with finite density. Using the effective action in a nuclear matter, we calculate the decay constant and pi mass as functions of the chemical potential. The relation between the chemical potential and the density of a nuclear matter is firstly given here. We find that f(pi) and m(pi) monotonously decrease as nuclear matter density increases. The result is consistent with the usual assumption that the chiral symmetry is gradually restored as the density of a nuclear matter increases.
124731696
The effective gluon propagator in the global color symmetry model
It is shown that the effective gluon propagator in the global color symmetry model can be calculated in the instanton dilute liquid approximation. The calculated effective gluon propagator is consistent with the general command on the qualitative features of the gluon propagator, i.e., (i) the gluon propagator is significantly enhanced at small space-like k(2), and (ii) for k(2) > 1.5 GeV2 the perturbative results are quantitatively reliable.
121445421
Study of Topological Structure of Vacuum by Lattice QCD
Overlap fermions and improved 5Li cooling are compared, which exhibits that these two filter methods can produce similar structures. Then the overlap fermions and improved 5Li cooling are combined to calculate the topological charge and identify the structure of the vacuum. The results are consistent with instanton liquid model.
119391728
Quantum Version of Gauge Invariance and Nucleon Internal Structure
The conflict between cononical commutation relation and gauge invariance, which both the momentum and angular momentum of quark and gluon should satisfy, is clarified. The quantum version of gauge invariance is studied. The gauge independence of the matrix elements of quark momentum and angular momentum operators between physical states are proved. We suggest to use the canonical quark momentum and angular momentum distributions to describe the nucleon internal structure in order to establish an internal consistent description of hadron spectroscopy and hadron structure. The same problem for the atomic spectroscopy and structure is discussed.
123819304
QCD INTERACTION IN PION-DEUTERON ELASTIC-SCATTERING
The pion-deuteron elastic scattering matrix element is under consideration in the framework of QCD. The interactions including the perturbative effect and nonperturbative contributions of gluon condensate and quark condensate in the scattering process are discussed. The interaction operators are given.
118391627
Measurement of hadron composition in charged jets from pp collisions with the ALICE experiment
Abstract We report the first measurement of charged pion, kaon and (anti-)proton production in jets from hadron colliders. The measurement was carried out with the ALICE detector using 2 × 10 8 minimum bias pp collisions at a centre-of-mass energy of s = 7 TeV at the LHC. We present the π, K and p transverse momentum ( p T ) spectra, as well as the spectra of the reduced momentum ( z ch ≡ p T track / p T,jet ch ), in charged jets of p T between 5–20 GeV/c. The measurement is compared to Monte Carlo calculations.
20926318
Natural Higgs mass in supersymmetry from nondecoupling effects.
The Higgs mass implies fine-tuning for minimal theories of weak-scale supersymmetry (SUSY). Nondecoupling effects can boost the Higgs mass when new states interact with the Higgs boson, but new sources of SUSY breaking that accompany such extensions threaten naturalness. We show that two singlets with a Dirac mass can increase the Higgs mass while maintaining naturalness in the presence of large SUSY breaking in the singlet sector. We explore the modified Higgs phenomenology of this scenario, which we call the "Dirac next-to-minimal supersymmetric standard model."
119116044
Energy loss signals in the ALICETRD
Abstract We present the energy loss measurements with the ALICE TRD in the β γ range 1–10 4 , where β = v / c and γ = 1 / 1 − β 2 . The measurements are conducted in three different scenarios: (1)with pions and electrons from testbeams; (2)with protons, pions and electrons in proton–proton collisions at center-of-mass energy 7 TeV; (3)with muons detected in ALICE cosmic runs. In the testbeam and cosmic ray measurements, ionization energy loss (d E /d x ) signal as well as ionization energy loss plus transition radiation (d E /d x +TR) signal are measured. With cosmic muons the onset of TR is observed. Signals from TeV cosmic muons are consistent with those from GeV electrons in the other measurements. Numerical descriptions of the signal spectra and the β γ - dependence of the most probable signals are also presented.
53654264
Neutrino mass anarchy and the Universe
A bstractWe study the consequence of the neutrino mass anarchy on cosmology, in particular the total mass of neutrinos and baryon asymmetry through leptogenesis. We require independence of measure in each mass matrix elements in addition to the basis independence, which uniquely picks the Gaussian measure. A simple approximate U(1) flavor symmetry makes leptogenesis highly successful. Correlations between the baryon asymmetry and the light-neutrino quantities are investigated. We also discuss possible implications of recently suggested large total mass of neutrinos by the SDSS/BOSS data.
118605527
How to use the Standard Model effective field theory
A bstractWe present a practical three-step procedure of using the Standard Model effective field theory (SM EFT) to connect ultraviolet (UV) models of new physics with weak scale precision observables. With this procedure, one can interpret precision measurements as constraints on a given UV model. We give a detailed explanation for calculating the effective action up to one-loop order in a manifestly gauge covariant fashion. This covariant derivative expansion method dramatically simplifies the process of matching a UV model with the SM EFT, and also makes available a universal formalism that is easy to use for a variety of UV models. A few general aspects of RG running effects and choosing operator bases are discussed. Finally, we provide mapping results between the bosonic sector of the SM EFT and a complete set of precision electroweak and Higgs observables to which present and near future experiments are sensitive. Many results and tools which should prove useful to those wishing to use the SM EFT are detailed in several appendices.