Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTotal and differential cross sections of the $boldsymbol{dpto {}^3}textrm{He},boldsymbol{eta}$ reaction at excess energies between 1 and 15 MeV
73
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
New high precision total and differential cross sections are reported for the $dpto {}^3textrm{He},eta$ reaction close to threshold. The measurements were performed using the magnetic spectrometer ANKE, which is an internal fixed target facility at the COSY cooler synchrotron. The data were taken for deuteron beam momenta between $3.14641~textrm{GeV}/c$ and $3.20416~textrm{GeV}/c$, which corresponds to the range in excess energy $Q$ for this reaction between $1.14~textrm{MeV}$ and $15.01~textrm{MeV}$. The normalization was established through the measurement in parallel of deuteron-proton elastic scattering and this was checked through the study of the $dpto {}^3textrm{He},pi^0$ reaction. The previously indicated possible change of sign of the slope of the differential cross sections near the production threshold, which could be explained by a rapid variation of the $s$- and $p$-wave interference term, is not confirmed by the new data. The energy dependence of the total cross section and the $90^{circ}$ slope parameter are well explained by describing the final state interaction in terms of a complex Jost function and the results are significant in the discussion of $eta$-mesic nuclei. In combination with recently published WASA-at-COSY data [P. Adlarson $et, al.$, Phys. Lett. B 782, 297 (2018)], a smooth variation of the slope parameter is achieved up to an excess energy of $80.9~textrm{MeV}$.
rate research
Read More
New data on both total and differential cross sections of the production of $eta$ mesons in proton-deuteron fusion to ${}^3text{He},eta$ in the excess energy region $13.6;text{MeV}leq Q_eta leq 80.9;text{MeV}$ are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Julich, using a proton beam at 15 different beam momenta between $p_p = 1.60;text{GeV}/c$ and $p_p = 1.74;text{GeV}/c$. While significant structure of the total cross section is observed in the energy region $20;text{MeV}lesssim Q_eta lesssim 60;text{MeV}$, a previously reported sharp variation around $Q_etaapprox 50;text{MeV}$ cannot be confirmed. Angular distributions show the typical forward-peaking that was reported elsewhere. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a large interval.
The neutron total cross sections $sigma_{tot}$ of $^{16,18}$O, $^{58,64}$Ni, $^{103}$Rh, and $^{112,124}$Sn have been measured at the Los Alamos Neutron Science Center (LANSCE) from low to intermediate energies (3 $leq E_{lab} leq$ 450 MeV) by leveraging waveform-digitizer technology. The $sigma_{tot}$ relative differences between isotopes are presented, revealing additional information about the isovector components needed for an accurate optical-model description away from stability. Digitizer-enabled $sigma_{tot}$-measurement techniques are discussed and a series of uncertainty-quantified dispersive optical model (DOM) analyses using these new data is presented, validating the use of the DOM for modeling light systems ($^{16,18}$O) and systems with open neutron shells ($^{58,64}$Ni and $^{112,124}$Sn). The valence-nucleon spectroscopic factors extracted for each isotope reaffirm the usefulness of high-energy proton reaction cross sections for characterizing depletion from the mean-field expectation.
The eta-prime meson production in the reaction pp-->pp eta-prime has been studied at excess energies of Q = 26.5, 32.5 and 46.6 MeV using the internal beam facility COSY-11 at the cooler synchrotron COSY. The total cross sections as well as one angular distribution for the highest Q-value are presented. The excitation function of the near threshold data can be described by a pure s-wave phase space distribution with the inclusion of the proton-proton final state interaction and Coulomb effects. The obtained angular distribution of the eta-prime mesons is also consistent with pure s-wave production.
New data on the production of single neutral pions in the $pdrightarrow{}^3textrm{He},pi^0$ reaction are presented. For fifteen proton beam momenta between $p_p=1.60;textrm{GeV}/c$ and $p_p=1.74;textrm{GeV}/c$, differential cross sections are determined over a large fraction of the backward hemisphere. Since the only previous systematic measurements of single-pion production at these energies were made in collinear kinematics, the present work constitutes a significant extension of the current knowledge on this reaction. Even this far above the production threshold, significant changes are found in the behaviour of the angular distributions over small intervals in beam momentum.
New precise unpolarised differential cross sections of deuteron-proton elastic scattering have been measured at 16 different deuteron beam momenta between $p_d = 3120.17;textrm{MeV}/c$ and $p_d =3204.16;textrm{MeV}/c$ at the COoler SYnchrotron COSY of the Forschungszentrum Julich. The data, which were taken using the magnetic spectrometer ANKE, cover the equivalent range in proton kinetic energies from $T_p = 882.2;textrm{MeV}$ to $T_p = 918.3;textrm{MeV}$. The experimental results are analysed theoretically using the Glauber diffraction model with accurate nucleon-nucleon input. The theoretical cross section at $T_p = 900;textrm{MeV}$ agrees very well with the experimental one at low momentum transfers $|t| <0.2;(textrm{GeV}/c)^2$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
