Coherent pion production in proton–deuteron collisions (original) (raw)
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Two-pion production in proton-proton collisions with a polarized beam
The European Physical Journal A, 2008
The two-pion production reaction pp → ppπ + π − was measured with a polarized proton beam at Tp ≈ 750 and 800 MeV using the short version of the COSY-TOF spectrometer. The implementation of a delayed-pulse technique for Quirl and central calorimeter provided positive π + identification in addition to the standard particle identification, energy determination as well as time-of-flight and angle measurements. Thus all four-momenta of the emerging particles could be determined with 1-4 overconstraints. Total and differential cross-sections as well as angular distributions of the vector analyzing power have been obtained. They are compared to previous data and theoretical calculations. In contrast to predictions we find significant analyzing-power values up to Ay = 0.3. The data taken in the energy region of the excitation of the Roper resonance confirm that its dominant ππ decay channel is N * → N σ. PACS. 13.75.Cs Nucleon-nucleon interactions (including antinucleons, deuterons, etc.) -14.20.Gk Baryon resonances with S = 0 -25.10.+s Nuclear reactions involving few-nucleon systems -25.40.Ep Inelastic proton scattering a
Two-pion production in deuteron-deuteron collisions at low energies
The European Physical Journal A, 2006
The cross-section for the dd → 4 He ππ reaction is estimated near threshold in a two-step model where a pion created in a first interaction produces a second pion in a subsequent interaction. This approach, which describes well the rates of 2π and η production in the pd → 3 He ππ and dd → 4 He η reactions, leads to predictions that are much too low compared to experiment. Alternatives to this and the double-∆ model will have to be sought to explain these data.
Vector and tensor analysing power of (d, p) reactions and deuteron D-state effects
Nuclear Physics A, 1973
The vector and tensor analysing power was measured for (d, p) reactions on 9Be, ~2C, 160, 19F, ZSMg, 2sSi and 4°Ca for lab reaction angles from 0 ° to 50 ° at 12.3 MeV incident deuteron energy. Fifteen transitions were studied including orbital angular momentum transfers In = 0, 1,2, 3. The experimental results were analysed in terms of distorted-wave theory including deuteron D-state effects. The calculations show that the deuteron D-state cannot be ignored in the description of the tensor analysing power. The j-dependence of D-state effects is discussed. NUCLEAR REACTIONS 9Be, J2C, 160, 19F, 25Mg, 2aSi, 4°Ca (polarized d, p), E = 12.3 MeV, measured analysing powers iT11 (0), T2o(O), 7"22 (0). Enriched 25Mg and '*°Ca targets. Deduced importance of D-state effects.
Analyzing power measurements in pion deuteron absorption at low energies
Physical review, 1994
As part of an experimental study of the~NN system, the pion-deuteron breakup reaction~+d~pn~+ was investigated at intermediate energies. Distributions of the vector analyzing power i T» versus outgoing proton momentum P are presented for 36 harp angle pairs in the range of scattering angles 20'~9"~51', 62'~0~124' at 228 and 134 MeV. These include 7 previously unmeasured angle pairs at 228 MeV and 20 new pairs at 134 MeV. In all regions of overlap with previous measurements, there is excellent agreement. There is generally excellent agreement with relativistic Faddeev predictions, except in the np final-state interaction region at 228 MeV. This is in contrast to the cross-section measurements, which are not well described by the theory.
2006
Vector and tensor analysing powers of the ~ dp → (pp)n (charge–exchange) and ~ dp → (pn)p (non–charge–exchange) breakup reactions have been measured with the ANKE spectrometer at the COSY ring at a deuteron beam energy of 1170MeV for small momentum transfers to the low excitation energy (pp) or (pn) systems. A quantitative understanding of the values of Axx and Ayy for the charge–exchange reaction is provided by impulse approximation calculations. The data suggest that spin–flip isospin–flip transitions, which dominate the charge–exchange breakup of the deuteron, are also important in the non–charge–exchange reaction. 1 Corresponding author: d.chiladze@fz-juelich.de Preprint submitted to Elsevier Preprint 15 March 2006
Vector and tensor analysing powers in deuteron–proton breakup reactions at intermediate energies
Physics Letters B, 2006
Vector and tensor analysing powers of the dp → (pp)n (charge-exchange) and dp → (pn)p (non-charge-exchange) breakup reactions have been measured with the ANKE spectrometer at the COSY ring at a deuteron beam energy of 1170 MeV for small momentum transfers to the low excitation energy (pp) or (pn) systems. A quantitative understanding of the values of A xx and A yy for the charge-exchange reaction is provided by impulse approximation calculations. The data suggest that spin-flip isospin-flip transitions, which dominate the charge-exchange breakup of the deuteron, are also important in the non-charge-exchange reaction.
Nuclear Physics B, 1978
Measurements are presented of the inclusive n 0 production cross section, in the transverse momentum range 2.3 <~ PT ~< 4.5 GeV/c, for dd and dp interactions at total c.m. energies ofx/s = 52.7 GeV and x/s ---63.2 GeV, and for pp interactions at ~/s = 52.7 GeV. The produced 7r 0's are detected by identifying both protons from the decay ~r 0 --, 3'3". As in pp interactions, the data can be adequately described by a p~nf(x T) dependence with n ~_ 8. The data are approximately consistent with the expectations of free nucleon scattering. No significant differences are observed in either the charged or the neutral particle distributions associated with ~r O, for dd, dp and pp interactions.
Deuteron yields from LHC: Continuum correlations and in-medium effects
arXiv (Cornell University), 2022
To explain the production of light nuclei in heavy-ion collisions at extreme energies, we focus on the deuteron case. A Gibbs ensemble at chemical freeze-out is a prerequisite to investigate the non-equilibrium evolution of the expanding fireball. Quantum statistical approaches allow to describe correlations including bound state formation in the strongly interacting and hot system. We consider the virial approach to evaluate proton-neutron correlations. In generalization of the treatment of protons in pionic matter (pion-proton puzzle), the influence of the pion environment on deuteron-like correlations is evaluated using data for the pion-deuteron scattering phase shifts. Calculated yields for deuteron production are compared with the ones observed at the LHC.