Search results for "baryon"

New evidence for a narrow state of mass 2.02 GeV/c2

1993

Abstract We report evidence for the existence of a narrow p p state with a mass of 2.02 GeV/c2 and a width of about 0.02 GeV/c2, produced centrally in π+p(π−p) interactions at 20(12) GeV/c in several final states, proceeding via baryon exchange mechanism, and that could be interpreted as a baryonium candidate. The data come from the analysis of WA56 experiment made at the CERN Ω spectrometer.

Decay properties of exoticN≃28 S and Cl nuclei and theCa48/46Ca abundance ratio

1993

Beta-decay half-lives and \ensuremath{\beta}-delayed neutron-emission probabilities of the very neutron-rich nuclei $^{44}\mathrm{S}$ and $^{45--47}\mathrm{Cl}$ have been measured. These isotopes, which lie at or close to the N=28 magic shell, were produced in interactions of a 60 MeV/u $^{48}\mathrm{Ca}$ beam from GANIL (Grand Acc\'el\'erateur National d'Ions Lourds) with a $^{64}\mathrm{Ni}$ target, and were separated by the doubly achromatic spectrometer LISE (Ligne d'Ions Super Epluch\'es). Their decay was studied by a \ensuremath{\beta}-n time correlation measurement. The results are compared to recent model predictions and indicate a rapid weakening of the N=28 shell effect below $_{2…

Description of πp→Δ(1232)π and πp→Δ(1232)ρ(770) reaction proceeding via baryon exchange mechanism

1991

We analyze the available experimental data on the backward production processes πN→Δπ and πN→ Δπ in the framework of the strong-cut Reggeized absorption model, which is based on the exchange of the baryon Regge trajectoriesNα and Δδ with the associated cuts. The model describes rather well the data on the differential cross sections at incident π momenta ranging from 2.15 to 20 GeV/c. An essential contribution of Δδ exchange even at small energies (Elab of the order of a few GeV) is found. A model-independent analysis of data confirms this fenomena.

Observation of charmless baryonic decays B(s)0→pp¯h+h′−

2017

Decays of B0 and Bs0 mesons to the charmless baryonic final states pp¯h+h′-, where h and h′ each denote a kaon or a pion, are searched for using the LHCb detector. The analysis is based on a sample of proton-proton collision data collected at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  fb-1. Four-body charmless baryonic Bs0 decays are observed for the first time. The decays Bs0→pp¯K+K-, Bs0→pp¯K±π∓, B0→pp¯K±π∓ and B0→pp¯π+π- are observed with a significance greater than 5 standard deviations; evidence at 4.1 standard deviations is found for the B0→pp¯K+K- decay and an upper limit is set on the branching fraction for Bs0→pp¯π+π-. Branching fraction…

A test of charge-parity-time invariance at the atto-electronvolt scale

2017

We developed a novel fast measurement procedure for cyclotron frequency comparisons of two individual particles in a Penning trap, which enabled us to compare the charge-to-mass ratio of the proton and the antiproton with a fractional precision of 69 parts per trillion. To date this is the most precise test of charge-parity-time invariance using baryons. Our measurements were performed at cyclotron frequencies of about 30 MHz, which means that charge-parity-time symmetry holds at the atto-electronvolt scale.

Baryon resonances in nuclei

2005

The field of baryon resonances in nuclei is reviewed. Theoretical developments and experimental evidence as well are discussed. Special emphasis is laid on electromagnetic processes for the two nucleon system. Some aspects of real isobars in nuclei are touched upon.

10.8 Conclusion

2008

Structure ofIn112nucleus

1988

The \ensuremath{\gamma}-ray spectra of the $^{112}\mathrm{Cd}$(p,n\ensuremath{\gamma}${)}^{112}$In and $^{109}\mathrm{Ag}$(\ensuremath{\alpha},n\ensuremath{\gamma}${)}^{112}$In reactions were measured with Ge(Li) spectrometers for bombarding energies of 4.8 MeV protons and 17.1 MeV \ensuremath{\alpha} particles. The energies and relative intensities of 79 $^{112}\mathrm{In}$ \ensuremath{\gamma}-ray transitions have been determined. The electron spectra were measured with combined magnet plus Si(Li) as well as superconducting magnetic lens plus Si(Li) spectrometers. Internal conversion coefficients of 40 $^{112}\mathrm{In}$ transitions have been determined, and the level scheme of $^{112}\ma…

C12(γ,p)11B cross section from 80 to 157 MeV

1995

The $^{12}\mathrm{C}$(\ensuremath{\gamma},p${)}^{11}$B differential cross section has been measured over proton angles ranging from 58\ifmmode^\circ\else\textdegree\fi{} to 128\ifmmode^\circ\else\textdegree\fi{}, using tagged photons of energy 80--157 MeV, for low-lying regions of residual excitation energy in $^{11}\mathrm{B}$. The data have been compared with four different types of calculation. It is shown that scaling of the cross section with momentum mismatch occurs for both the ground-state and excited-state data.

Hybridization ofsd- andfp-shell proton orbitals in the systemS36+37Cl

1993

Experimental and theoretical evidence is presented that the proton exchange is strongly enhanced by a mixing of single-particle configurations in $^{37}\mathrm{Cl}$ (in the system $^{36}\mathrm{S}$${+}^{37}$Cl, which is shown to be the clearest example of hybridization in nuclear physics. The experimental data on elastic and inelastic transfer are only reproduced if the complete set of single-particle states (${\mathit{d}}_{3/2}$,${\mathit{s}}_{1/2}$,${\mathit{f}}_{7/2}$,${\mathit{p}}_{3/2}$,${\mathit{f}}_{5/2}$, and ${\mathit{p}}_{1/2}$) is included in a coupled-reaction-channel calculation. The strong enhancement is explained by the hybridization of orbits of different parity. In a two-ce…