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Feasibility to detect D * (2010) at SIS100. Yu. Vertogradova, V. Pozdnyakov (JINR). Outline:. method to search for D * (2010) +/- input for the study results conclusion. method to search for D * (2010) +/-.
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Feasibility to detect D*(2010) at SIS100 Yu. Vertogradova, V. Pozdnyakov (JINR) Outline: method to search for D*(2010)+/- input for the study results conclusion
method to search for D*(2010)+/- the approach (often called as a ‘soft-pion’ method) is to look at following decay chain: D*(2010)+into D0p+ with D0 into K-p+ (and cc) Pro: constraint/window on D0 mass should decrease background and requirements on particle ID; constraint on soft-pion and kaon charges - they are opposite; soft-pion is not too soft in fixed-target exp (CBM) Challenges: high vertex/impact resolution kaon/pion separation small expected yield so intensive beams are required Seems all these are met with CBM An example what we should see in an experiment
input for the study 1 MEvents of pC UrQMD and 10 kEvents pp generated by PYTHIA with D* produced inside, both samples at proton energies of 30 GeV Then some kinematical criteria have been applied to generated samples – some of them to involve CBM acceptance (polar angles of particles are above 4-5 degrees etc. ); momentum domains were advised by PYTHIA; minimum particle momenta to roughly satisfy CBM efficiencies With UrQMD events a ‘mixer’ was produced and ‘events’ are collected according to kaon-pion (only they are considered ) multiplicities (as expected with UrQMD) Smooth D* yield 109 ‘mixed’ with 10-6 D* per an event Qkaon x Qpion Unlike signs (signal) Same signs (bkgr)
results More tight conditions (10-7 D* per an event) with more (1010)UrQMD ‘mixed’ statistics D0candidates are somewhere within 50 MeV window around nominal mass Additional criteria (on kaon, pion coming from D0 are required) PV D0 D* 10-7 D* per event psoft inside 1010 pC UrQMD events Smear (100 mm of s) production vertex to simulate impacts of tracks and require ‘impact’ of kaon and pion from D0 to be behind 50 mm from zero (i.e. Vertex is somehow reconstructed)
conclusion • several constraints coming from physics of D*(2010)+-> D0p+ -> K-p+p+ decay-chain allow to detect D* mesons produced at SIS100 in pC collisions with CBM • detailed simulation has to be carried out • with inclusion of four-prong D0 decay (acceptance will be definitely smaller but Br is twice) • for AuAu collisions at SIS100 energies as well