The ATLAS data quality defect database system

The ATLAS experiment at the Large Hadron Collider has implemented a new system for recording information on detector status and data quality, and for transmitting this information to users performing physics analysis. This system revolves around the concept of “defects,” which are well-defined, fine-grained, unambiguous occurrences affecting the quality of recorded data. The motivation, implementation, and operation of this system is described.     

Constraining parameter space of the little Higgs model using data from tera-Z factory and ILC

The Standard Model(SM) prediction on the forward-backward asymmetry for bˉb production(A b FB) is well consistent with the data of LEP at the Z-pole, but deviates from the data at√s =89.55 and 92.95 Ge V which are slightly away from the pole. This deviation implies that there is still room for new physics. We calculate the A b FB at the vicinity of the Z-pole in the little Higgs model as well as other measurable parameters such as R b and R c,by which we may constrain the parameter space of the little Higgs model. This can be further tested in the newly proposed tera-Z factory. With the fitted parameters we further make predictions on A b FB and A t FB for tˉt production at the International Linear Collider(ILC).     

Constraining symmetry energy at subnormal density by isovector giant dipole resonances of spherical nuclei

In our previous study, the deduced Langevin equation has been applied to investigate the isoscalar giant monopole resonance. In the current study, the framework is extended to study the isovector giant dipole resonance(IVGDR). The potential well in the IVGDR is calculated by separating the neutron and proton densities based on the Hartree-Fock ground state. Subsequently, the Langevin equation is solved self-consistently, resulting in the centroid energy of the IVGDR without width. The symmetry energy around the density of 0.02 fm~(-3) contributes the most to the potential well in the IVGDR. By comparison with the updated experimental data of IVGDR energies in spherical nuclei, the calculations within 37 sets of Skyrme functionals suggest the symmetry energy to be in the range of 8.13-9.54 MeV at a density of 0.02 fm~(-3).     

Photonuclear data and modern physics of giant resonances

The results of the development (“renaissance”) of giant-resonance physics are briefly discussed from the point of view of their application to creating a photonuclear database. It is indicated that part of the recommendations from corresponding libraries of data are not at the level of the present-day status of giant-resonance physics. A Lorentzian parametrization of the most reliable experimental data on isovector M1 resonances is constructed for seven spherical nuclei, and it is shown that the widths of M1 resonances are severalfold, sometimes an order of magnitude, smaller than the value of Γ₀ = 4 MeV, which was recommended for all nuclei. The need for microscopically taking into account configurations more complex than those that are included within the standard random-phase approximation or within the quasiparticle random-phase approximation is emphasized. To be more precise, it is necessary to take into account coupling to phonons, since this changes the temperature dependence of the resonance width in relation to that which was used earlier and since, without this, one cannot explain the properties of pygmy dipole resonances in the region of the nucleon binding energy. Our calculations of the average energies of the pygmy dipole resonances in the Ca and Sn isotopes within the microscopic extended theory of finite Fermi systems reveal that the inclusion of coupling to phonons reduces these energies considerably toward the improvement of agreement with experimental data. The idea of creating a library of photonuclear data for unstable nuclei, including fission fragments, on the basis of the extended theory of finite Fermi systems is discussed in connection with the fact that information necessary for fitting the parameters of phenomenological theories is absent or insufficient for such nuclei.     

Baryon resonances and their properties from the CLAS data

The study of the baryon spectrum is a fundamental part of the scientific program in Hall B at Jefferson Lab. By using the CLAS detector, reactions involving electromagnetic production of exclusive hadronic final states in the kinematic region of baryon resonances have been extensively measured, with the purpose of extracting information on non-strange baryon excited states. Some selected topics in the N ^* CLAS experimental program are outlined and corresponding new experimental results are reported and briefly discussed.     

Constraining cosmological parameters with observational data including weak lensing effects

In this Letter, we study the cosmological implications of the 100 square degree Weak Lensing survey (the CFHTLS-Wide, RCS, VIRMOS-DESCART and GaBoDS surveys). We combine these weak lensing data with the cosmic microwave background (CMB) measurements from the WMAP5, BOOMERanG, CBI, VSA, ACBAR, the SDSS LRG matter power spectrum and the Type Ia Supernoave (SNIa) data with the “Union” compilation (307 sample), using the Markov Chain Monte Carlo method to determine the cosmological parameters, such as the equation-of-state (EoS) of dark energy w  , the density fluctuation amplitude σ₈${\sigma }_8$, the total neutrino mass ∑mν$\sum m_{\nu }$ and the parameters associated with the power spectrum of the primordial fluctuations. Our results show that the ΛCDM model remains a good fit to all of these data. In a flat universe, we obtain a tight limit on the constant EoS of dark energy, w=−0.97±0.041$w=-0.97\pm 0.041$ (1σ  ). For the dynamical dark energy model with time evolving EoS parameterized as wde(a)=w₀+wa(1−a)$w_{\mathrm{de}}(a)=w_0+w_a(1-a)$, we find that the best-fit values are w₀=−1.064$w_0=-1.064$ and wa=0.375$w_a=0.375$, implying the mildly preference of Quintom model whose EoS gets across the cosmological constant boundary during evolution. Regarding the total neutrino mass limit, we obtain the upper limit, ∑mν<0.471 eV$\sum m_{\nu }<0.471\text{eV}$ (95% C.L.) within the framework of the flat ΛCDM model. Due to the obvious degeneracies between the neutrino mass and the EoS of dark energy model, this upper limit will be relaxed by a factor of 2 in the framework of dynamical dark energy models. Assuming that the primordial fluctuations are adiabatic with a power law spectrum, within the ΛCDM model, we find that the upper limit on the ratio of the tensor to scalar is r<0.35$r<0.35$ (95% C.L.) and the inflationary models with the slope ns?1$n_s?1$ are excluded at more than 2σ   confidence level. In this Letter we pay particular attention to the contribution from the weak lensing data and find that the current weak lensing data do improve the constraints on matter density Ωm${\Omega }_m$, σ₈${\sigma }_8$, ∑mν$\sum m_{\nu }$, and the EoS of dark energy.     

Constraining the low-energy pion electromagnetic form factor with spacelike data

The pionic contribution to the g-2 of the muon involves a certain integral over the modulus squared of F_π(t), the electromagnetic form factor of the pion. We extend techniques that use cut-plane analyticity properties of F_π(t) in order to account for present day estimates of the pionic contribution and experimental information at a finite number of points in the spacelike region. Using data from several experiments over a large kinematic range for |t|, we find bounds on the expansion coefficients of F_π(t), sub-leading to the charge radius. The value of one of these coefficients in chiral perturbation theory respects these bounds. Furthermore, we present a sensitivity analysis to the inputs. A brief comparison with results in the literature that use observables other than the g-2 and timelike data is presented.     

Constraining chameleon field driven warm inflation with Planck 2018 data

The European Physical Journal C - We study the Yukawa model with one scalar and one axial scalar fields, coupled to N copies of Dirac fermions, in curved spacetime background. The theory possesses...     

Calculation of resonances using isospectral potentials

We present a nice method for calculation of resonances by solving potentials isospectral with the original one. Application to three-dimensional finite square well immediately indicates its efficacy in calculation of broad resonant states.     

Top-quark mass measurement using events with missing transverse energy and jets at CDF

We present a measurement of the top-quark mass using a sample of t ?t events in 5.7 fb(-1) of integrated luminosity from p ?p collisions at the Fermilab Tevatron with √s=1.96 TeV and collected by the CDF II Detector. We select events having large missing transverse energy, and four, five, or six jets with at least one jet tagged as coming from a b quark, and reject events with identified charged leptons. This analysis considers events from the semileptonic t ?t decay channel, including events that contain tau leptons. The measurement is based on a multidimensional template method. We fit the data to signal templates of varying top-quark masses and background templates, and measure a top-quark mass of M(top)=172.32±2.4(stat)±1.0(syst) GeV/c(2).     

Constraining extended theories of gravity using Solar System tests

Solar System tests give nowadays constraints on the estimated value of the cosmological constant, which can be accurately derived from different experiments regarding gravitational redshift, light deflection, gravitational time-delay and geodesic precession. Assuming that each reasonable theory of gravitation should satisfy Solar System tests, we use these limits on the estimated value of the cosmological constant to constrain extended theories of Gravity, which are nowadays studied as possible theories for cosmological models and provide viable solutions to the cosmological constant problem and the explanation of the present acceleration of the Universe. We obtain that the estimated values, from Solar System tests, for the parameters appearing in the extended theories of Gravity are orders of magnitude bigger than the values obtained in the framework of cosmologically relevant theories.     

Investigation of proton channeling using nuclear-reaction resonances

To investigate orientation effects, an approach based on the measurements of γ-ray yields following the excitation of “narrow" isolated resonances in the reactions occurring on the nuclei of interstitial impurity atoms, that occupy certain positions in a crystal, has been proposed. The carbon atoms were shown to be located in octahedral interstitial sites of the Re-0.4 at. % ¹³C monocrystalline solution. The proton flux distribution in the (0001) channel was investigated via the 1.7476 MeV resonance of the ¹³C(p,γ)¹⁴N reaction. Some particular qualities of the reaction yield were found to be dependent upon the proton energy. The method of measurement of the electronic stopping power of channeled particles has been deduced. The γ-ray yield of the resonance reactions induced by the channeled protons was shown to be dependent on the amplitude of the thermal vibrations of carbon atoms.