Inclusive production of vector mesons in π+ p interactions at 250 GeV/c

Measurement of meson resonance production in $$\pi ^-+$$ π - + C interactions at SPS energies

“…At intermediate x F (0.4 < x F < 0.7) the ρ 0 production is underestimated by up to −60%. It is interesting to note that even if QGSJet II-04, Sibyll 2.3 and Epos-LHC were tuned to π + +p data from NA22 [17], these models cannot reproduce the measurement presented here. The large underestimation in QGSJet II-04 is mainly for non-forward ρ 0 production which is not treated explicitly in the model.…”

“…14 for ρ 0 and ω mesons. The two other experiments shown are NA22 [17] and LEBC-EHS (NA27) [57], both of which used a hydrogen target. NA22 had a π + beam at 250 GeV/c while LEBC-EHS had a π − beam at 360 GeV/c.…”

“…These results are the first π − + C measurements taken in this energy range and are important The error bars show the statistical, the bands indicate systematic uncertainties (where available). The black points are from this experiment, blue squares are from NA22 [17], red triangles are from LEBC-EHS (NA27) [57]. ρ 0 spectra are shown on the left and ω spectra on the right to tune hadronic interaction models used to understand the measurements of cosmic-ray air showers.…”

“…One way to increase this number is to account for the production of baryons and antibaryons to decrease f em [12]. Another possibilty has been recently identified [13,14] by noting that accelerator data on π + + p interactions [15][16][17] indicate that most of the neutral mesons produced in the forward direction are not π 0 s but ρ 0 mesons. With ρ 0 decaying into π + π − this would imply that the energy of the leading particle is not transferred to the electromagnetic shower component as it would be in the case of neutral pions and corresponingly f em is decreased leading to more muons at ground level.…”

“…Ref. [27]) or protons as target [15][16][17]28], or did not discriminate between the different secondaries [29].…”