Scope: PWG
PWG-LF (Light Flavour Spectra)
Energy
2.76 TeV
System
Pb-Pb
Figure Group
Figure Image
Figure image (.eps)
Figure image (.pdf)
Figure Caption
Anti-Hypertriton invariant mass spectrum obtained from the reconstruction of its 3 body decay channel. The number of events selected is 19x10^6 (0-10%) in Pb-Pb collisions at 2.76 TeV (2011 data taking)
Detail description
Antihypertriton candidates are reconstructed in the mesonic weak charged 3 body decay channel antideuteron + antiproton + pion^{+}.
Analysis performed on LHC11h_2 using ESDs
Event selection:
- Trigger: kCentral, kSemiCentral
- Centrality: 0-10%, 10-50%
- z primary vertex: -10 < z_pv < 10 cm
Track cuts:
- TPCrefit: kTRUE
- Reject kink daughters
- Number of TPC clusters > 80
- chi2/clusters < 5
- pseudorapidity |eta| < 0.9
Special additional cuts for pion candidates:
- Number of TPC clusters > 100
- 0.2 <pT < 1.2 GeV/c
Decay products are identified with the TPC (3\sigma inclusion) and further cuts are applied to select good tripler candidates (e.g. DCA between tracks, angle between tracks)
Additional selection on decay topology is applied:
- cosine of pointing angle > 0.999
- ct > 1 cm
- candidate hypertriton pT range: 2 - 10 GeV/c
- normalized decay lenght > 3
- rapidity |y| < 0.5