Notes from the HonexComb meeting 25 Oct 2022
- News and communications:
- Jacek went through the scientific topics of the group summarising the recent and future activities of the group. The frequency has been intermittent due to the lockdown and other issues but now we are planning to resume the original monthly schedule of the meetings.
- Quarkonia feed-downs: F.Damas
- Florian presented one of the Honexcomb/Strong activities which is the study of the feeddowns rates from higher mass quarkonium states to ground states. Florian studied the bottomonium states and charmonium states, collaborating with Caetano (U.Santiago). There is a discussion about the values of Upsilon feed-down at zero-pT, and possibility to extrapolate the value of the cross-sections of the P-wave states in order to extrapolate ds/dpT at zero pT.
- Update on combined charm cross-section in pp collisions at 5TeV: Jeremy Wilkinson
- Jeremy gives an update on the global analysis using several charmed hadrons cross section measured at ALICE, LHCBb and CMS to obtain a common result using extrapolation with Pythia at a special tune in the regions where data are not present. For the first time the extrapolation uncertainties, evaluated with different tunes of Pythia, are discussed and added to the result. The first draft of the paper is also briefly discussed, with a submission expected for winter/spring 2023.
- There is a discussion on the evaluation of the upper and lower limit of the band needed for the extrapolation which is obtained using the omega_c. Some suggestions from Johanna on how to get a better estimate and reduce the uncertainty (use results from existing MC generators on omega_c vs Xi_c). Another suggestion is to extract also dscc/dy. The shape of the Lambda_c rapidity distribution in the Monash tune is also discussed, Christian will be looking into this.
- Studies of Lambda_c on D0: Sandor Lokos
- Sandor looked at the ratio of the states in the subject in particular investigating the different behaviour of the ratio as a function of pT in LHCb and ALICE. He proposed a model which include coalescence and can maybe describe both LHCb and ALICE, very interesting. Idea is to compare the model with results from pp data, maybe at high multiplicity.
- Questions:
- PMB: what is the mass of the charm quark used in the models for the particles used?
- How is hadronization realised in the model?
- Exclusive ditau production: Yuriy Volkotrub
- Yuriy presented in detail gamma + gamma tau tau measurements of anomalous magnetic moments of leptons in Pb+Pb UPC collisions by ATLAS (2018 run) and CMS (2015 run) Coll. He aims at combining their results to reduce statistical and systematic uncertainties using BLUE and TRExFitter tools.
- Questions:
- JO: what about 2018 data by CMS? IG-B: CMS will not release new data soon.
- AOBs: procedure to make public data to be discussed next time
Next honexcomb: most probably on Nov. 29 tbd
There are minutes attached to this event.
Show them.
