Search results for "pion"

Neutron skin studies of medium and heavy nuclei

2014

The recent PREX experiment at JLab has demonstrated the sensitivity of parity violating electron scattering to the neutron density, meanwhile outlining its major experimental challenges. On the other side, intermediate energy photons are an ideal probe for studying the properties of strongly interacting matter from the nuclear scale down to the sub-nuclear components of the nucleus. Among others coherent pion photoproduction can provide information on the existence and nature of neutron skins in nuclei. The simultaneous combination of different techniques allows a systematic determination across the periodic table thus benchmarking modern calculation. Recently a systematic investigation of …

Eiropas basketbola meistarsacīkstes Rīgā 1937. gadā no 2. līdz 7. maijam Sporta namā

1937

Studio di alcuni aspetti dell’Enoturismo in Sicilia.

2008

Effects of chronic administration with high doses of testosterone propionate on behavioral and physiological parameters in mice with differing basal …

2003

The effects of testosterone propionate, an anabolic-androgenic steroid, on the behavior displayed during a social encounter by gonadally intact male mice were investigated. Animals were distributed into three groups according to their attack latency in a pre-screening test (high-, moderate-, and low-attacking mice) and each group received weekly injections of 60 or 120 mg/kg of testosterone or sesame oil for 10 weeks. Behavioral tests were then carried out. Afterwards, organs were weighed and blood samples collected in order to obtain hormonal data. Treatment had a differential impact on attack in the three groups of animals. Only the high-attacking testosterone-treated mice showed lower to…

High energy neutrino yields from astrophysical sources

2006

We calculate the yield and flavour content of high energy neutrinos produced in astrophysical sources with negligible magnetic fields varying their interaction depth. We take into account the scattering of secondaries on background photons as well as the direct production of neutrinos in decays of charm mesons. If multiple scattering of nucleons becomes important, the neutrino spectra from meson and muon decays are strongly modified with respect to transparent sources. Characteristic for neutrino sources containing photons as scattering targets is a strong energy-dependence of the ratio R0 of νμ and νe fluxes at the sources, ranging from R0=μ/e~0 below threshold to R0~4 close to the energy …

Search for heavy neutrinos in \(\pi ^{ + } \to \mu ^{ + }\nu \) decay and status of lepton universality test in the PIENU experiment

2019

International audience; In the present work of the PIENU experiment, heavy neutrinos were sought in pion decays \(\pi ^{ + } \to \mu ^{ + }\nu \). No evidence for extra peak was found in the muon kinetic energy spectrum and 90% confidence level upper limits were set on the neutrino mixing matrix \(|U_{\mu i}|^{2}\) in the mass range of 15.7 to 33.8 MeV/c^2, improving an order of magnitude over previous experiments. Current status of lepton universality test is also reported.

Nucleon mass and pion-nucleon sigma term from a chiral analysis of lattice QCD data

2013

The pion mass dependence of the nucleon mass within the covariant SU(2) baryon chiral perturbation theory both without and with explicit Delta(1232) degrees of freedom up to order p(4) is investigated. By fitting to a comprehensive set of lattice QCD data in 2 and 2 + 1 flavors from several collaborations, for pion masses M-pi < 420 MeV, we obtain low energy constants of natural size that are compatible with pion-nucleon scattering data. Our results are consistent with the rather linear pion mass dependence showed by lattice QCD. In the 2 flavor case we have also performed simultaneous fits to nucleon mass and sigma(pi N) data. As a result of our analysis, which encompasses the study of fin…

Nuclear cross sections in 16O for β beam neutrinos at intermediate energies

2006

The nuclear cross sections for charged lepton production induced by $\beta$ beam neutrinos (anti-neutrinos) in $^{16}$O have been presented at intermediate energies corresponding to the Lorentz boost factor $\gamma<250 (150)$. The calculations for quasi-elastic lepton production includes the effect of Pauli blocking, Fermi motion and renormalization of weak transition strengths in the nuclear medium. The calculations for the inelastic lepton production is done in the $\Delta$ dominance model. The renormalization of $\Delta$ properties in a nuclear medium and final state interactions of pions with the final nucleus are taken into account. The results may be useful in performing feasibility s…

Misure spettrometriche gamma di concentrazioni radionuclidiche in campioni ambientali e alimentari in situazioni di emergenza

2013

Nucleon isovector charges and twist-2 matrix elements with Nf=2+1 dynamical Wilson quarks

2019

We present results from a lattice QCD study of nucleon matrix elements at vanishing momentum transfer for local and twist-2 isovector operator insertions. Computations are performed on gauge ensembles with nonperturbatively improved ${N}_{f}=2+1$ Wilson fermions, covering four values of the lattice spacing and pion masses down to ${M}_{\ensuremath{\pi}}\ensuremath{\approx}200\text{ }\text{ }\mathrm{MeV}$. Several source-sink separations (typically $\ensuremath{\sim}1.0$ to $\ensuremath{\sim}1.5\text{ }\text{ }\mathrm{fm}$) allow us to assess excited-state contamination. Results on individual ensembles are obtained from simultaneous two-state fits across all observables and all available sou…