Baryon resonances in carbon-carbon collisions at4.2GeV/cper nucleon

Analysis of Δ0(1232) production in collisions of protons with carbon nuclei at 4.2 GeV/c

“…7. As seen from this figure, the relative number of nucleons excited to ∆ 0 at freeze-out in p+ 12 C collisions at 4 2 GeV/c is compatible with those obtained in Refs [22,24,39,43]. In [67] the dependences of the multiplicities of charged particles on Q value in p+ 12 C collisions at 4 2 GeV/c were investigated, where Q = + − − − evap with + and − being the numbers of positively and negatively (singly) charged particles in an event, respectively, and evap  the number of protons with lab < 300 MeV/c classified as the evaporated ones.…”

“…2 . This is due to a large combinatorial background from uncorrelated p π − pairs as was also shown earlier for 16 O+ p collisions [41] at 3 25 A GeV/c, C+C [39], 4 He+C [43], and C+Ta [42] collisions at 4 2 A GeV/c, π − + 12 C interactions at 40 GeV/c [40]. To reduce such contribution as much as possible, the method of analyzing an angle between the proton and pion was used as done successfully in Refs.…”

“…To reduce such contribution as much as possible, the method of analyzing an angle between the proton and pion was used as done successfully in Refs. [39][40][41][42][43] to extract the mass distribution of ∆ 0 (1232). If the ∆ resonance decays in flight, the angle α between the outgoing proton and pion, in the laboratory frame, is defined by…”

Comparison of characteristics of Δ0(1232) produced in p 12C and d 12C collisions at 4.2 A GeV/c

“…Comparison of the fractions of π − mesons coming from Δ 0 (1232) decays, presented in Table 5, with the other published data [4,6,19,43], including central heavy-ion collisions, is illustrated in Fig. 5.…”

“…Comparison of the fractions of nucleons excited to Δ 0 at freeze-out estimated in [21,22] for p 12 C and d 12 C collisions at 4.2 A GeV/c with those obtained in other experiments with different sets of colliding nuclei at various incident energies [4,6,19,43] is shown in Fig. 6.…”