Comparison of π±, K± and p,p production in the central rapidity region in hadron-hadron collisions and in e+e− annihilation

We compare the p_T dependence of pion, kaon and proton production cross sections in the central rapidity region in e⁺e⁻ annihilation events and in proton-proton collisions at ISR energies. We find similarities both in the p_T dependence of cross sections and in the particle composition as a function of p_T, in agreement with the hypothesis of a universal mechanism of particle production.     

Two-pion spectra for the reaction π− p → π0π0 n at a pion momentum of 38 GeV/c and combined analysis of GAMS, Crystal Barrel, and BNL data

We perform a K-matrix analysis of IJ ^PC =00⁺⁺, 10⁺⁺, 02⁺⁺, and 12⁺⁺ meson partial waves using GAMS data on π^? p → π⁰π⁰ n, ηηn, ηη'n that are supplemented with BNL data on π^? p → K $\bar K$ n and Crystal Barrel data on p $\bar p$ (at rest) → π⁰π⁰π⁰, π⁰ηη, π⁰π⁰η. The positions of the amplitude poles (physical resonances) are determined, together with the positions of the K-matrix poles (bare states) and the values of barestate couplings to two-meson channels. The nonet classification of the bare states found in the present analysis is discussed.     

Joint production of ϕ mesons andπ ±,π 0,p,\bar p,K s 0 andK ± in hadronic interactions

The joint production of ? mesons andπ ^±,π ⁰,p, \(\bar p\) ,K _s ⁰ andK ^± is investigated using a sample of 600,000 inclusive ? meson events obtained in hadron Be interactions with incidentπ ^±,p, \(\bar p\) andK ^± beams. Evidence is presented for the joint production of ? mesons and strange particles produced with non-strange incident beams. With incidentK ^± beam the number of additional strange particles is suppressed. The results are found to be in agreement with the qualitative predictions of a parton fusion model. The comparison with the Lund model for lowp _T processes is fair.     

Update on two-zero textures of the Majorana neutrino mass matrix in light of recent T2K,Super-Kamiokande and NOνA results

The latest results from atmospheric and accelerator neutrino experiments indicate that the normal neutrino mass ordering m_1 m_2 m_3, a maximal leptonic CP-violating phase δ = 270° and the second octant of neutrino mixing angle θ_23 45° are favored. In light of new experimental results, we update previous phenomenological studies on two-zero textures of the Majorana neutrino mass matrix M-_ν, in the flavor basis where the charged-lepton mass matrix M_l is diagonal. When the 1σ ranges of neutrino mixing parameters are taken into account, only four(i.e., A_(1,2)and B_(2,4)) among seven two-zero patterns of Mνshow the aforementioned features of neutrino mass spectrum, mixing angle θ_23and CP-violating phase δ, and thus are compatible with the latest neutrino oscillation data. The correlative relations among neutrino masses and mixing parameters have been derived analytically for these four patterns, and the allowed regions of neutrino mixing angles and the CP-violating phase are also given. Possible realizations of four viable two-zero textures via non-Abelian discrete flavor symmetries are discussed.     

Searching for new physics in D^0→μ^＋ μ^-,e^＋e^-,μ^±e at BES and/or the super charm-tau factory

In contrast with B0-ˉB0, Bs-ˉBs mixing where the standard model（SM） contributions overwhelm that of the new physics beyond standard model（BSM）, a measured relatively large D0-ˉD0mixing where the SM contribution is negligible, definitely implies the existence of the new physics BSM. It is natural to consider that the rare decays of D meson might be more sensitive to new physics, and the decay mode D0→μ＋μ-could be an ideal area to search for new physics because it is a flavor changing process. In this work we look for a trace of the new physics BSM in the leptonic decays of D0. Concretely we discuss the contributions of unparticle or an extra gauge boson Z while imposing the constraints set by fitting the D0-ˉD0mixing data. We find that the long-distance SM effects for D0→lˉl still exceed those contributions of the BSM under consideration, but for a double-flavor changing process such as D0→μ±e, the new physics contribution would be significant.     

Searching for new physics in D~0→μ~+ μ~-,e~+e~-,μ~±e~■ at BES and/or the super charm-tau factory

In contrast with B0-ˉB0, Bs-ˉBs mixing where the standard model(SM) contributions overwhelm that of the new physics beyond standard model(BSM), a measured relatively large D0-ˉD0mixing where the SM contribution is negligible, definitely implies the existence of the new physics BSM. It is natural to consider that the rare decays of D meson might be more sensitive to new physics, and the decay mode D0→μ+μ-could be an ideal area to search for new physics because it is a flavor changing process. In this work we look for a trace of the new physics BSM in the leptonic decays of D0. Concretely we discuss the contributions of unparticle or an extra gauge boson Z while imposing the constraints set by fitting the D0-ˉD0mixing data. We find that the long-distance SM effects for D0→lˉl still exceed those contributions of the BSM under consideration, but for a double-flavor changing process such as D0→μ±e, the new physics contribution would be significant.     

Near barrier fission channels (Jπ, K) in 238U for spins Jπ=0+, 1−, and 2+ from (e,e′f) angular correlation measurements

Complete in- and out-of-plane fission fragment angular correlations for ²³⁸U have been measured in (e, e′f) coincidence experiments for momentum transfers q_eff=0.20 and 0.28 fm⁻ and excitation energies ω=5.5–15 MeV. A combined analysis with previously extracted E1 and E2/E0 multipole strength distributions yields strength distributions for all 6 near barrier fission channels (J^π, K) = (0⁺, 0), (1⁻, 0), (1⁻, 1), (2⁺, 0), (2⁺, 1), and (2⁺, 2) up to ≈8 MeV. An estim ate of the respective fission barriers, deduced from the increase of the fission cross sections, is given.     

Tetraquark-based analysis and predictions of the cross sections and distributions for the processes e+e-→Υ(1S)(π+π-,K+K-,ηπ0) near Υ(5S)

We calculate the cross sections and final state distributions for the processes e(+)e(-)→Υ(1S)×(π(+)π(-),K(+)K(-),ηπ(0)) near the Υ(5S) resonance based on the tetraquark hypothesis. This framework is used to analyze the data on the Υ(1S)π(+)π(-) and Υ(1S)K(+)K(-) final states [K.?F. Chen et al. (Belle Collaboration), Phys. Rev. Lett. 100, 112001 (2008); I. Adachi et al. (Belle Collaboration), Phys. Rev. D 82, 091106 (2010).], yielding good fits. Dimeson invariant-mass spectra in these processes are shown to be dominated by the corresponding light scalar and tensor states. The resulting correlations among the cross sections are worked out. We also predict σ(e(+)e(-)→Υ(1S)K(+)K(-))/σ(e(+)e(-)→Υ(1S)K(0)K(0))=1/4. These features provide crucial tests of the tetraquark framework and can be searched for in the currently available and forthcoming data from the B factories.     

Elastic ν<Subscript>μ</Subscript><Emphasis Type="Italic">e</Emphasis> scattering as a source for determining the muonic neutrino mass and investigation of its electromagnetic properties

Electroweak (EW) and electromagnetic (EM) contributions to the cross sections of elastic scattering of muonic neutrinos by electron are analyzed. The effect of the neutrino mass and root-mean-square charge radius on the angular and energy distributions of product electrons and the total scattering cross sections is considered. The possibility of measuring the muon neutrino magnetic moment μ_ν by selecting its contribution to the ν_μ e-scattering cross sections is analyzed.     

Experimental He-pressure broadening for the R(10) and P(2) lines in the ν3 band of CO2, and experimental pressure shifts for R(10) measured at several temperatures between 300 K and 100 K

Helium broadening coefficients for the R(10) and the P(2) lines in the ν₃ band of ¹³CO₂ have been measured over a large range of temperature (70 K-300 K). Helium pressure shifts for the R(10) line at several temperatures between 100 K and 300 K have also been determined. These measurements were obtained with a cold Herriott cell, using the collisional cooling technique to reach the lowest temperatures. They provide an extended dataset for the temperature dependence of widths and shifts. This dataset was compared to theoretical He-broadening coefficients combining quantum scattering calculations and the latest potential energy surface for the system He-CO₂ from Korona et al. [T. Korona, R. Moszynski, F. Thibault, J.-M. Maunay, B. Bussery-Honvault, J. Boissoles, P.E.S. Wormer, J. Chem. Phys. 115 (2001) 3074-3084].