arXiv subjects

Mario Gaspero

Publications and source records attributed to Mario Gaspero.

4 recordsLinked to original sources

arXiv2010

Study of a Narrow pi+ pi- Peak at about 755 MeV/c**2 in pbar n --> 2 pi+ 3 pi- Annihilation at Rest

A narrow peak in the pi+ pi- mass distribution was seen by the Rome-Syracuse Collaboration in pbar n --> 2 pi+ 3 pi- annihilation at rest in 1970. It was ignored for 40 years. The reanalysis of this peak finds that it has the mass 757.4 +- 2.8_stat +- 1.1_sys MeV/c**2 and a width consistent with the experimental resolution. The evidence of the peak is 5.2 standard deviations. The peak is generated in (1.03 +- 0.21_stat +- 0.21_sys)% of the pbar n annihilations at rest. No spin analysis is possible with the statistics of the experiment but there are arguments suggesting that it has JP = 0+.

hep-ex↗

arXiv2010

Study of the D0 --> pi+ pi- pi0 decay at BABAR

The Dalitz-plot of the Decay D0 --> pi+ pi- pi0 measured by the BABAR Collaboration shows the structure of a final state having quantum numbers IG JPC = 0- 0--. An isospin analysis of the Daliz-plot finds that the I = 0 contribution is about 96%. This high I = 0 contribution is unexpected because the weak interaction violates the isospin.

hep-ex↗

arXiv2009

Study of a narrow pi+ pi- peak at about 755 MeV/c^2 in bar-p n --> 2 pi+ 3 pi- annihilation at rest

A narrow peak in the pi+ pi- mass distribution was seen by the Rome-Syracuse Collaboration in bar-p n --> 2 pi+ 3 pi- annihilation at rest 39 years ago. The reanalysis of this peak finds a mass of 757.4 +- 2.6 MeV/c^2 and a width slightly narrower than the experimental resolution. The evidence of the peak is 5.2 standard deviations. This state is generated in (12.4 +- 2.4)% of the bar-p n --> 2 pi+ 3 pi- annihilations at rest. No spin analysis is possible with the statistics of the experiment.

hep-ex↗

arXiv2008

Isospin analysis of D0 decay to three pions

The final state of the decay D0 --> pi+ pi- pi0 is analyzed in terms of isospin eigenstates. It is shown that the final state is dominated by the isospin-0 component. This suggests that isospin considerations may provide insight into this and perhaps other $\Dz$-meson decay. We also discuss the isospin nature of the nonresonant contribution in the decay, which can be further understood by studying the decay D0 --> pi0 pi0 pi0.

hep-ph↗