Charmonium and Exotics Working Group Meeting
: May 2, 2014
: Bertram Kopf, Christof Motzko, Diego Bettoni, Elisa Fioravanti, Klaus Goetzen, Martin Galuska, Marc Pelizaeus, Torsten Schroeder
Elisa presented the status of the chic -> J/psi gamma analysis, where angular distributions have to be measured. She presented the efficiency corrected distributions of the relevant decay angles. The selection is in good shape. Background of pion channels with cross sections of about 0.1 mb will be considered in the next step. It was suggested to extract the decay amplitude parameters from the distributions and compare them to the input values of the simulation. This will define a figure of merit for the analysis.
Malte presented the status of the benchmark studies for glueball searches. So far he studied the reaction pbar p -> phi phi eta at a beam momentum of 15 GeV
/c.The cross section is assumed to be 1nb. Main background is coming from pi+ pi- pi+ pi- pi0 and other mult-pion final states with estimated cross ssections of 1 mb. Malte started to produce and analyze signal and background events. The figure of merit is 100 reconstructed events with a signal-noise ratio better than 1. During his talk he pointed out that a kinematic fit with a constraint to the beam momentum and energy (4C) plus a mass constraint to the eta would help to reject background, but is currently not supported by the kinematic fitter. Klaus will have a look to this issue together with Ralf. It was suggested to use the significance of the signal as a figure of merit instead of the two quantities defined by Malte.
Klaus summarized the activities of the GSI group. The group is investigating charmonium resonances with different recoil systems. The basic framework for the event selection has been setup and data production for the signal and background channles will start next week.
At the next collaboration meeting presentations of the analyses should be given during the parallel sessions. So far Anastasia, Malte, Klaus and Elisa will give a presentation.
The next meeting will be on May 9, 2014 at 11:30 am.
[Addendum: After the meeting Anastasia and Christof summarized the status of their analyses via email. Anastasia focused on pbarp -> h_c -> pi+ pi- pi0 and pbarp -> h_c -> 2(pi+ pi-) pi0. Simulation with small statistic looks promising. Data production has been started at the computing cluster in Mainz. Christof started with pbar p -> phi(2170) pi+ pi- -> phi pi+ pi- pi+ pi- and pbar p -> phi(2170) pi0 -> phi pi+ pi- pi0 in search for hybrids. He carried out first background studies with DPM events.]
Material for discussion
- 01 May 2014