Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of the Partial Cross Sections s(TT), s(LT) and [s(T)+epsilon*s(L)] of the p(e,e pi+)n Reaction in the Delta(1232) Resonance
278
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We report new precision p(e,e pi+})n measurements in the Delta(1232) resonance at Q2 = 0.127(GeV/c)2 obtained at the MIT-Bates Out-Of-Plane scattering facility. These are the lowest, but non-zero, Q2 measurements in the pi+ channel. The data offer new tests of the theoretical calculations, particularly of the background amplitude contributions. The chiral effective field theory and Sato-Lee model calculations are not in agreement with this experiment.
rate research
Read More
The recoil proton polarization has been measured in the p (vec e,evec p) pi^0 reaction in parallel kinematics around W = 1232 MeV, Q^2 = 0.121 (GeV/c)^2 and epsilon = 0.718 using the polarized c.w. electron beam of the Mainz Microtron. Due to the spin precession in a magnetic spectrometer, all three proton polarization components P_x/P_e = (-11.4 pm 1.3 pm 1.4) %, P_y = (-43.1 pm 1.3 pm 2.2) %, and P_z/P_e = (56.2 pm 1.5 pm 2.6) % could be measured simultaneously. The Coulomb quadrupole to magnetic dipole ratio CMR = (-6.4pm 0.7_{stat}pm 0.8_{syst}) % was determined from P_x in the framework of the Mainz Unitary Isobar Model. The consistency among the reduced polarizations and the extraction of the ratio of longitudinal to transverse response is discussed.
The process $e^+e^- to pi^+pi^-pi^0eta$ is studied in the center-of-mass energy region below 2 GeV with the SND detector at the VEPP-2000 $e^+e^-$ collider. The four intermediate states contribute to this process: $omegaeta$, $phieta$, $a_0(980)rho$, and a structureless $pi^+pi^-pi^0eta$ state. We measure the total $e^+e^- to pi^+pi^-pi^0eta$ cross section and the cross sections for its components: $omegaeta$, $phieta$, and a sum of $a_0(980)rho$ and the structureless state. Our results are in agreement with previous measurements and have comparable or better accuracies.
We study $D_{s}^{+}$ decays to final states involving the $eta$ with a 482$,$pb$^{-1}$ data sample collected at $sqrt{s}$ = 4.009$,$GeV with the mbox{BESIII} detector at the BEPCII collider. We measure the branching fractions $mathcal{B}(D^+_{s}rightarrow etaX)$ = (8.8$pm$1.8$pm$0.5)$%$ and $mathcal{B}(D_{s}^{+}rightarrow etarho^{+})$ = ($5.8pm1.4pm0.4$)$%$ where the first uncertainty is statistical and the second is systematic. In addition, we estimate an upper limit on the non-resonant branching ratio $mathcal{B}(D_{s}^{+}rightarrow etapi^+pi^0)<5.1%$ at the 90$%$ confidence level. Our results are consistent with CLEOs recent measurements and help to resolve the disagreement between the theoretical prediction and CLEOs previous measurement of $mathcal{B}(D_{s}^{+}rightarrow etarho^{+})$.
The cross sections of the process $e^{+}e^{-} to K_{S}^{0}K_{L}^{0}$ are measured at fifteen center-of-mass energies $sqrt{s}$ from $2.00$ to $3.08~{rm GeV}$ with the BESIII detector at the Beijing Electron Positron Collider (BEPCII). The results are found to be consistent with those obtained by BaBar. A resonant structure around $2.2~{rm GeV}$ is observed, with a mass and width of $2273.7 pm 5.7 pm 19.3~{rm MeV}/c^2$ and $86 pm 44 pm 51~{rm MeV}$, respectively, where the first uncertainties are statistical and the second ones are systematic. The product of its radiative width ($Gamma_{e^+e^-}$) with its branching fraction to $K_{S}^{0}K_{L}^{0}$ ($Br_{K_{S}^{0}K_{L}^{0}}$) is $0.9 pm 0.6 pm 0.7~{rm eV}$.
Using 586 $textrm{pb}^{-1}$ of $e^{+}e^{-}$ collision data acquired at $sqrt{s}=4.170$ GeV with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of $D_{s}^{*+} to D_{s}^{+} e^{+} e^{-}$ with a significance of $5.3 sigma$. The ratio of branching fractions $calB(D_{s}^{*+} to D_{s}^{+} e^{+} e^{-}) / calB(D_{s}^{*+} to D_{s}^{+} gamma)$ is measured to be $[ 0.72^{+0.15}_{-0.13} (textrm{stat}) pm 0.10 (textrm{syst})]%$, which is consistent with theoretical expectations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
