The Charge Form Factor of the Neutron at Low Momentum Transfer from the 2H⃗(e⃗,e′n)p^{2}\vec{\rm H}(\vec{\rm e},{\rm e}'{\rm n}){\rm p} Reaction

We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio $G^{n}_{E}/G^{n}_{M}$ was extracted from the beam-target vector asymmetry $A_{ed}^{V}$ at four-momentum transfers $Q^{2}=0.14$, 0.20, 0.29 and 0.42 (GeV/c)$^{2}$.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let

Measurement of the proton electric to magnetic form factor ratio from \vec ^1H(\vec e, e'p)

We report the first precision measurement of the proton electric to magnetic form factor ratio from spin-dependent elastic scattering of longitudinally polarized electrons from a polarized hydrogen internal gas target. The measurement was performed at the MIT-Bates South Hall Ring over a range of four-momentum transfer squared $Q^2$ from 0.15 to 0.65 (GeV/c)$^2$. Significantly improved results on the proton electric and magnetic form factors are obtained in combination with previous cross-section data on elastic electron-proton scattering in the same $Q^2$ region.Comment: 4 pages, 2 figures, submitted to PR

Višenukleonska emisija nakon pionske apsorpcije u N, Ar i Xe

Positive pion absorption was studied in an almost 4π geometry allowing simultaneous measurements of various charge and neutral multiplicities. Total absorption cross sections and its decomposition into the most important channels is determined. The results are presented for N, Ar and Xe nuclei at incident pion energies of 118,162 and 239 MeV. The role of multinucleon emission in the absorption process is emphasized.Proučava se pionska apsorpcija s blizu 4π detekcijom koja dozvoljava istovremeno mjerenje raznih nabojskih i neutralnih višestrukosti. Određuju se ukupni udarni presjeci i njihovo razlaganje u najvažnije kanale. Predstavljaju se rezultati za jezgre N, Ar i Xe na energijama 118,162 i 239 MeV. Ističe se uloga višenukleonske emisije u procesu apsorpcije

Višenukleonska emisija nakon pionske apsorpcije u N, Ar i Xe

Positive pion absorption was studied in an almost 4π geometry allowing simultaneous measurements of various charge and neutral multiplicities. Total absorption cross sections and its decomposition into the most important channels is determined. The results are presented for N, Ar and Xe nuclei at incident pion energies of 118,162 and 239 MeV. The role of multinucleon emission in the absorption process is emphasized.Proučava se pionska apsorpcija s blizu 4π detekcijom koja dozvoljava istovremeno mjerenje raznih nabojskih i neutralnih višestrukosti. Određuju se ukupni udarni presjeci i njihovo razlaganje u najvažnije kanale. Predstavljaju se rezultati za jezgre N, Ar i Xe na energijama 118,162 i 239 MeV. Ističe se uloga višenukleonske emisije u procesu apsorpcije

Measurement of Longitudinal Spin Transfer to Lambda Hyperons in Deep-Inelastic Lepton Scattering

Spin transfer in deep-inelastic Lambda electroproduction has been studied with the HERMES detector using the 27.6 GeV polarized positron beam in the HERA storage ring. For an average fractional energy transfer = 0.45, the longitudinal spin transfer from the virtual photon to the Lambda has been extracted. The spin transfer along the Lambda momentum direction is found to be 0.11 +/- 0.17 (stat) +/- 0.03 (sys); similar values are found for other possible choices for the longitudinal spin direction of the Lambda. This result is the most precise value obtained to date from deep-inelastic scattering with charged lepton beams, and is sensitive to polarized up quark fragmentation to hyperon states. The experimental result is found to be in general agreement with various models of the Lambda spin content, and is consistent with the assumption of helicity conservation in the fragmentation process.Comment: 8 pages, 3 figures; new version has an expanded discussion and small format change

Pionska apsorpcija u 4He

This paper presents a large solid angle measurement of the positive pion absorption cross-section on 4He and its decomposition into partial channels. A large fraction of the absorption cross-section at incident pion kinetic energies of Tπ+ =70, 118, 162, 239, and 330 MeV is due to multinucleon channels.Daju se ishodi mjerenja pod velikim prostornim kutom udarnog presjeka za apsorpciju pozitivnih piona u He4 i razdjela na pojedine kanale. Velik dio apsorpcijskog udarnog presjeka za energije upadnih piona od Tπ+ =70, 118, 162, 239 i 330 MeV je posljedica višenukleonskih kanala

Measurement of the Vector and Tensor Asymmetries at Large Missing Momentum in Quasielastic (\u3cem\u3ee\u3c/em\u3e\u3csup\u3e→\u3c/sup\u3e,\u3cem\u3ee\u27p\u3c/em\u3e Electron Scattering from Deuterium

We report the measurement of the beam-vector and tensor asymmetries AVed and ATd in quasielastic (e→,e′p) electrodisintegration of the deuteron at the MIT-Bates Linear Accelerator Center up to missing momentum of 500  MeV/c. Data were collected simultaneously over a momentum transfer range 0.1 \u3c Q2 \u3c 0.5  (GeV/c)2 with the Bates Large Acceptance Spectrometer Toroid using an internal deuterium gas target polarized sequentially in both vector and tensor states. The data are compared with calculations. The beam-vector asymmetry AVed is found to be directly sensitive to the D-wave component of the deuteron and has a zero crossing at a missing momentum of about 320  MeV/c, as predicted. The tensor asymmetry ATd at large missing momentum is found to be dominated by the influence of the tensor force in the neutron-proton final-state interaction. The new data provide a strong constraint on theoretical models

Pionska apsorpcija u 4He

This paper presents a large solid angle measurement of the positive pion absorption cross-section on 4He and its decomposition into partial channels. A large fraction of the absorption cross-section at incident pion kinetic energies of Tπ+ =70, 118, 162, 239, and 330 MeV is due to multinucleon channels.Daju se ishodi mjerenja pod velikim prostornim kutom udarnog presjeka za apsorpciju pozitivnih piona u He4 i razdjela na pojedine kanale. Velik dio apsorpcijskog udarnog presjeka za energije upadnih piona od Tπ+ =70, 118, 162, 239 i 330 MeV je posljedica višenukleonskih kanala