Alice Upgrade

1. Alice Upgrade

2. Physics Motivation • There are two main physics issues we propose to address which are uniquely accessible (among others) by upgraded ALICE detector: • Measurement of heavy-flavour transport parameters– separately for charm and beauty – • diffusion coefficients via azimuthal asymmetry • energy loss via RAA gives access to understanding of the nature of matter created in heavy-ion collisions and its equation of state • Measurement of direct real and virtual gammas • QGP radiation – temperature • vector-meson spectral function – wewill verify, using the QCD sum rules, lattice QCD predictions at zero baryon density on disappearance of the vacuum condensate – restoration of chiral symmetry and generation of hadron masses

3. Heavy-flavour measurements • Yields of D-mesons (incl. Ds), Lc, Xc, B-mesons, Lb • in medium hadronization of heavy-flavours • heavy-flavour radial flow • Elliptic flow of D and B • thermalization of heavy-flavour quarks • coupling strength to the medium • viscosity-to-entropy ratio • Transverse momentum spectra – RAA • transition from diffusion to energy-loss regime • quark vs. gluon energy loss • collisional vs. radiative energy loss • Better under control than light-quark sector

4. Charmoniummeasurement • J/y, y’, and cc states down to low (zero) transverse momentum • yields and transverse momentum spectra– RAA • statistical hadronization vs. dissociation/recombination scenario • transition between low and high transverse momenta • density dependence – central vs. forward production • elliptic flow • heavy-quark diffusion coefficient

5. Dilepton measurement • yield of low-mass e+e- (virtual g) • by extrapolation yield of direct real g • temperature at different stages • integrated according the mass window • disentangle space-time evolution • contribution from cc pair – complementary measurement to HF • spectral function of r-meson – e+e-effective mass spectrum down to 200 MeV • from QCD sum rules axial-vector part • compare to lattice QCD calculations, where the modification of spectral function is caused by disappearance of vacuum condensate • observation of chiral-symmetry restoration

6. Additional measurements • Jets • Heavy-flavour tagged jets • detail comparison gluon vs. quark induced jets • heavy-flavour produced in fragmentation • Particle identified fragmentation functions • influence of media on fragmentations, • particle composition • g – jet correlations • jet energy recuperation at very low energies • Heavy-nuclear states • mass-4 and -5 (anti-)hypernuclei • search for H-dibaryon, Ln bound state, etc.

7. Observables

8. WG with Atlas and CMS • Representatives • Atlas: Peter Steinberg • CMS: Raphael Granier de Cassagnac, Gunther Roland • Alice: LoI editorial board • Meetings • May 9th – we informed our colleagues about Alice Upgrade Intentions https://indico.cern.ch/conferenceDisplay.py?confId=190561 • May 25th – we listen first reaction from Atlas and CMS https://indico.cern.ch/conferenceDisplay.py?confId=192476 • What we learned: • CMS: rate to storage manager and pixel limit few kHz (L1), to tape few100 Hz (HLT) • CMS: jets down to 25 GeV, maybe lower, 85% of missing energy pt > 0.5 GeV (tracking down to 0.3 GeV), jet study w.r.t. reaction plane, b jets > 50 GeV, g, Z, W – jet (up to 120 GeV), multi-jet correlations • CMS: lower cut-off for muons 3-4 GeV, forward 2 GeV, but lowering B field may help • CMS: p, K, p PID up to 1 GeV, strange up to 10 GeV, D mesons tbd • Atlas: similar constrains as CMS, rate to HLT 3 kHz, to tape O(500 Hz) • Atlas: jet, concentrate on high Et, g, Z – jet, tracking down to 0.5 GeV • Atlas: low-mass dileptons difficult, electron ID not extended to low pt yet • Atlas: PID limited to low momentum region, muons limited as in CMS • Agreed to try comparison on performance figures (momentum, impact)

9. ALICE upgrade LoI • Physics motivation for running ALICE beyond LS2, with • running at 50 kHZ for PbPb collisions collecting 10 nb-1 or above (and 2 MHz for pp collisions) • continuous readout, inspecting all heavy-ion collisions • Feasibility to achieve presented physics goals by • upgrading of central barrel detectors (ITS and TPC) and of readout electronics of other detectors • upgrading of Trigger, HLTand DAQ systems, and offline computing • Three possible extensions of ALICE under study, will be considered by collaboration in September • VHMPID (to improve PID at higher momenta – identified RAA and jet fragmentation function) • Muon Forward Tracker (MFT) (complement low-mass dileptons in mm channel, b-production in forward region, lower background for J/y and y’) • Forward Calorimeter (FoCal) (study of very low-x region, colour-glass condensate)

10. Letter of Intent outline • Introduction (K. Safarik, P. Braun-Munzinger, P. Jacobs, L. Musa) • Physics Motivations • Heavy flavour (A. Dainese, G. Usai) - advanced draft • Quarkonia (A. Andronic)- draft of phys motivation • Low mass dileptons (H. Appelshaeuser) - draft of phys motivation • Jet physics (A. Morsch, M. Van Leeuwen, K. Klein-Boesing) - draft of phys motivation • Heavy Nuclear States (P.Braun-Munzinger) - draft of phys motivation • Detectors and Readout Electronics Upgrade (W. Riegler, L. Musa) - advanced draft • ITS, TPC Readout Plane, Electronics of TPC, TRD, TOF, EMCal, PHOS and Muons • DAQ, HLT & Offline (P. Vande Vyvre, T. Kollegger, F. Carminati) - advanced draft • Data processing, Data compression, Computing & Netowrking • Cost estimate, Resources, Schedule, Organization (W. Riegler, P. VandeVyvre, L. Musa)