Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userPrecise Measurements of Beam Spin Asymmetries in Semi-Inclusive $pi^0$ production
223
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial $sin phi_h$ amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle $phi_h$ of the produced neutral pion. The dependence of this amplitude on Bjorken $x$ and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.
rate research
Read More
We present recent results of single-spin asymmetry $A_N$ measurements in $pi^0$ inclusive production. Asymmetry was measured in $pi^-p$ and $pp$ interactions at 40 and 70 GeV correspondingly. Significant asymmetry was observed in the polarized target fragmentation region. The results are in agreement with universal threshold of single-spin asymmetry.
High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here the first multidimensional study of single $pi^+$ SIDIS data over a large kinematic range in $z$, $x_B$, $P_T$ and virtualities $Q^2$ ranging from 1 GeV$^2$ up to 7 GeV$^2$. In particular, the structure function ratio $F_{LU}^{sinphi}/F_{UU}$ has been determined, where $F_{LU}^{sinphi}$ is a twist-3 quantity that can reveal novel properties of quark-gluon correlations within the nucleon. The impact of the data on the evolving understanding of the underlying reaction mechanisms and their kinematic variation is explored using theoretical models for the different contributing transverse momentum dependent parton distribution functions.
A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum, and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously.
Single Spin Asymmetries (SSA) $A_N$ measured in the two reactions at the Protvino 70 GeV accelerator are presented. $A_N$ in the reaction $p+p(pol)->pi^0+X$ in the central region is close to zero within the error bars. SSA in the reaction $pi^- +p(pol)->pi^0+X$ in the polarized target fragmentation region is equal to $(-15 pm 4)%$ at $|x_F|>0.4$. There is an indication that the asymmetry arises at the same pion energy in the center of mass system.
A first measurement of the longitudinal beam spin asymmetry ALU in the semi-inclusive electroproduction of pairs of charged pions is reported. ALU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498 GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the sin(phiR) moments of ALU are extracted for the kinematic variables of interest in the valence quark region. The understanding of di-hadron production is essential for the interpretation of observables in single hadron production in semi-inclusive DIS, and pioneering measurements of single spin asymmetries in di-hadron production open a new avenue in studies of QCD dynamics.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
