arXiv subjects

A. Janata

Publications and source records attributed to A. Janata.

3 recordsLinked to original sources

arXiv2009

Collins and Sivers asymmetries for pions and kaons in muon-deuteron DIS

The measurements of the Collins and Sivers asymmetries of identified hadrons produced in deep-inelastic scattering of 160 GeV/c muons on a transversely polarised 6LiD target at COMPASS are presented. The results for charged pions and charged and neutral kaons correspond to all data available, which were collected from 2002 to 2004. For all final state particles both the Collins and Sivers asymmetries turn out to be small, compatible with zero within the statistical errors, in line with the previously published results for not identified charged hadrons, and with the expected cancellation between the u- and d-quark contributions.

hep-ex↗

arXiv2007

The reaction ${n} {p} \to {p} {p} π^{-}$ from threshold up to 570 MeV

The reaction ${n} {p} \to {p} {p} π^{-}$ has been studied in a kinematically complete measurement with a large acceptance time-of-flight spectrometer for incident neutron energies between threshold and 570 MeV. The proton-proton invariant mass distributions show a strong enhancement due to the pp($^{1}{S}_{0}$) final state interaction. A large anisotropy was found in the pion angular distributions in contrast to the reaction ${p}{p} \to {p}{p} π^{0}$. At small energies, a large forward/backward asymmetry has been observed. From the measured integrated cross section $σ({n}{p} \to {\rm p}{p} π^{-})$, the isoscalar cross section $σ_{01}$ has been extracted. Its energy dependence indicates that mainly partial waves with Sp final states contribute. Note: Due to a coding error, the differential cross sections ${d σ}/{d M_{pp}}$ as shown in Fig. 9 are too small by a factor of two, and inn Table 3 the differential cross sections ${d σ}/{d Ω_π^{*}}$ are too large by a factor of $10/2π$. The integrated cross sections and all conclusions remain unchanged. A corresponding erratum has been submitted and accepted by European Physics Journal.

nucl-ex↗

arXiv2001

Analysing powers for the reaction $\vec{\rm n} {\rm p} \to {\rm p} {\rm p} π^{-}$ and for np elastic scattering from 270 to 570 MeV

The analysing power of the reaction ${\rm n}{\rm p} \to {\rm p}{\rm p} π^{-}$ for neutron energies between threshold and 570 MeV has been determined using a transversely polarised neutron beam at PSI. The reaction has been studied in a kinematically complete measurement using a time-of-flight spectrometer with large acceptance. Analysing powers have been determined as a function of the c.m. pion angle in different regions of the proton-proton invariant mass. They are compared to other data from the reactions ${\rm n}{\rm p} \to {\rm p}{\rm p} π^{-}$ and ${{\rm p}{\rm p} \to {\rm p}{\rm p} π^{0}}$. The np elastic scattering analysing power was determined as a by-product of the measurements.

nucl-ex↗