Assuming that the π+π− photoproduction at forward angles and high energies is dominated by one pion exchange we calculate the π+π− mass distributions for low partial waves. Predictions of the model ...agree well with the experimental data which indicate that the S, P and D waves are dominated by the f0(980), ρ(770) and f2(1270), resonances respectively.
We present the coupled channel model of the scalar isovector resonance photoproduction including the πη, KK̅ and πη′ channels and calculate resulting mass distribution and the cross section in the πη ...channel. We show that the shape of this mass distribution, is strongly affected by the phase of background amplitude. We also discuss the effect of inclusion the πη′ channel on the overall isovector photoproduction process.
The search for correlations between secondary cosmic ray detection rates and seismic effects has long been a subject of investigation motivated by the hope of identifying a new precursor type that ...could feed a global early warning system against earthquakes. Here we show for the first time that the average variation of the cosmic ray detection rates correlates with the global seismic activity to be observed with a time lag of approximately two weeks, and that the significance of the effect varies with a periodicity resembling the undecenal solar cycle, with a shift in phase of around three years, exceeding 6 σ at local maxima. The precursor characteristics of the observed correlations point to a pioneer perspective of an early warning system against earthquakes.
Variations of secondary cosmic ray detection rates are periodically correlated with future global earthquake magnitude sum.
•The local changes of the cosmic ray flux correlate with the global seismic activity.•The cosmic signal correlates with the future seismic activity.•The effect lasts a few years and occurs with periodicity similar to the solar cycle.
We show that the cross section of the Δ(1230) production in the
γp
→
pπ
+
π
−
reaction at forward angles and with unpolarized photons can be described in terms of gauge invariant one pion
t
-channel ...exchange amplitudes. Proper description of the polarized cross sections requires, however, the inclusion of contributions from the baryon exchanges.
Backward angle (
u
-channel) scattering provides complementary information for studies of hadron spectroscopy and structure, but has been less comprehensively studied than the corresponding forward ...angle case. As a result, the physics of
u
-channel scattering poses a range of new experimental and theoretical opportunities and questions. We summarize recent progress in measuring and understanding high energy reactions with baryon charge exchange in the
u
-channel, as discussed in the first
Backward angle (u-channel) Physics Workshop
. In particular, we discuss backward angle measurements and their theoretical description via both hadronic models and the collinear factorization approach, and discuss planned future measurements of
u
-channel physics. Finally, we propose outstanding questions and challenges for
u
-channel physics.
We calculated the coupled channel photoproduction amplitudes of the scalar isovector resononace a0(980), which include the πη, K+K− and K0K̅0intermediate states. Based on them we obtained the mass ...distribution in the πη channel at photon energy Eγ=7 GeV, corresponding to energy accissible in new JLab experiments CLAS12 and GlueX. We also analyzed the shape of mass distribution as a function of the phase of the background amplitude.
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