Date

Collaboration

Observation of a near-threshold enhancement in the $e^+e^- \to \Lambda_c^+ \Lambda_c^-$ cross section using initial-state radiation

The Belle collaboration Pakhlova, G. ; Adachi, I. ; Aihara, H. ; et al.
Phys.Rev.Lett. 101 (2008) 172001, 2008.
Inspire Record 791660 DOI 10.17182/hepdata.21861

We report a measurement of the exclusive \$e^+e^- \to \Lambda_c^+ \Lambda_c^-$ cross section as a function of center-of-mass energy near the $\Lambda_c^+ \Lambda_c^-$ threshold. A clear peak with a significance of $8.8\sigma$ is observed in the $\Lambda_c^+ \Lambda_c^-$ invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of $M=(4634^{+8}_{-7} \mathrm{(stat.)} ^{+5}_{-8} \mathrm{(sys.)})\mevc$ and $\Gamma_{\mathrm{tot}}=(92^{+40}_{-24} \mathrm{(stat.)}^{+10}_{-21} \mathrm{(sys.)})\mev$ are determined. The analysis is based on a study of events with initial-state-radiation photons in a data sample collected with the Belle detector at the $\Upsilon(4S)$ resonance and nearby continuum with an integrated luminosity of 695 $\mathrm{fb}^{-1}$ at the KEKB asymmetric-energy $e^+e^_$ collider.

1 data table

Cross section for the exclusive process E+ E- --> LAMBDA/C+ LAMBDA/CBAR-.


Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle

The Belle collaboration Wang, X.L. ; Yuan, C.Z. ; Shen, C.P. ; et al.
Phys.Rev.Lett. 99 (2007) 142002, 2007.
Inspire Record 756643 DOI 10.17182/hepdata.51373

The cross section for e+e- to pi+ pi- psi(2S) between threshold and \sqrt{s}=5.5 GeV is measured using 673 fb^{-1} of data on and off the \Upsilon(4S) resonance collected with the Belle detector at KEKB. Two resonant structures are observed in the pi+ pi- psi(2S) invariant mass distribution, one at 4361\pm 9\pm 9 MeV/c2 with a width of 74\pm 15\pm 10 MeV/c2, and another at 4664\pm 11\pm 5 MeV/c2 with a width of 48\pm 15\pm 3 MeV/c2, if the mass spectrum is parameterized with the coherent sum of two Breit-Wigner functions. These values do not match those of any of the known charmonium states.

1 data table

Measured cross section.


Measurement of $e^+e^- \to \pi^+\pi^-J/\psi$ Cross Section via Initial State Radiation at Belle

The Belle collaboration Yuan, C.Z. ; Shen, C.P. ; Wang, P. ; et al.
Phys.Rev.Lett. 99 (2007) 182004, 2007.
Inspire Record 756012 DOI 10.17182/hepdata.50926

The cross section for e^+e^- to pi^+pi^-J/psi between 3.8 and 5.5 GeV/c^2 is measured using a 548 fb^{-1} data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c^2. A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower mass side of the 4.25 GeV enhancement.

1 data table

Measured cross section. Statistical errors only.


A measurement of the photonuclear interactions of 180-GeV muons in iron

Alexa, C. ; Anderson, K. ; Antonaki, A. ; et al.
Eur.Phys.J.C 28 (2003) 297-304, 2003.
Inspire Record 621812 DOI 10.17182/hepdata.43173

The energy spectrum and the cross section of photonuclear interactions of 180 GeV muons in iron were measured at the CERN SPS using prototype modules of the ATLAS hadron calorimeter. The differential

2 data tables

Measured differential cross section for fractional photonuclear muon energy loss.

Total photonuclear cross section which gives best agreement of energy loss with theory. See text of paper for details.