Post on 17-Jan-2016
Strangeness opportunities at the LHCStrangeness opportunities at the LHC
RIKEN BNL Research Center Workshop - BNL - 15/02/06
1. Strangeness at LHC energies Extrapolations / Motivations
2. Strange probes with ALICE Detector and Simulations
3. First p+p Collisions and beyondFirst measures to target
Strangeness in Collisions
Boris HIPPOLYTE, STRASBOURG
02/2006 RIKEN-BNL Research Center Workshop - BNL 2
Wroblewski factor extrapolation to LHC energies
Extrapolation at the LHCA+A ~0.45 p+p ~0.25
< >2
< >+< >λ s
ss
uu dd
Wroblewski factor:
Using thermal model description with corresponding system formalism (canonical or grand-canonical), extrapolation is straightforward.
Data compilation using Becattini et al., PR C64 (2001) 024901, hep-ph/0002267 and references therein
02/2006 RIKEN-BNL Research Center Workshop - BNL 3
Excitation functions of hyperons yields in A+A
dN/dy extrapolations at the LHCfor : 10~30for : 3~6for : 0.4~0.7
Expected modificationstotal multiplicity scalingnon-equilibrium scenario
02/2006 RIKEN-BNL Research Center Workshop - BNL 4
Equilibrium vs non−equilibrium scenarii in A+A
Eq. [ Oeschler et al., to be published ] [ Andronic et al., nucl-th/0511071 ]Non Eq. [ Rafelski et al., Eur. J. Phys. C45 (2006) 61 ]
Expectations at the LHC energies (eq.):
Tch ~170 MeV B ~1 MeV
Scenarii for s
Calculations fromKraus et al., (Eq.)Rafelski et al., (Non Eq.)
02/2006 RIKEN-BNL Research Center Workshop - BNL 5
Blast-Wave parameters <T> and Tfo extrapolation
Global trend for Blast-Wave parameters (<T> and Tfo) is clear
Excitation functions of the radial flow velocity and the kinetic freeze-outtemperature parameters for central Au+Au or Pb+Pb collisions.
Compilation from N. Xu
02/2006 RIKEN-BNL Research Center Workshop - BNL 6
Blast-Wave for Multi-Strange Baryons vs √sNN
G.E. Bruno J.Phys. G 31 (2005) s127 J. Speltz nucl-ex/0512037 S. Salur nucl-ex/0509036
Evolution of parameters up to LHC energies and systematics study for Tfo
02/2006 RIKEN-BNL Research Center Workshop - BNL 7
The central detectors of the ALICE experiment
Time ProjectionChamber
-0.9< < 0.9azimuth 2length 5 mactive volume 88 m3
02/2006 RIKEN-BNL Research Center Workshop - BNL 8
The central detectors of the ALICE experiment
Inner Tracking System
-0.9< < 0.9silicon layers 6
pixel/drift/strip 2/2/2 cells(M) 9.84/23/2.6
area 0.21/1.31/4.77 m3
02/2006 RIKEN-BNL Research Center Workshop - BNL 9
The central detectors of the ALICE experimentTransition-Radiation
Detector
-0.9< < 0.9azimuth 2length ~7 mactive area 736 m2
02/2006 RIKEN-BNL Research Center Workshop - BNL 10
The central detectors of the ALICE experiment
Time Of Flight
-0.9< < 0.9azimuth 2length 7.45 mactive area 141 m2
02/2006 RIKEN-BNL Research Center Workshop - BNL 11
The central detectors of the ALICE experiment
High-MomentumParticle Identification
Detector-0.6< < 0.6
azimuth 57.61°active area 10 m2
02/2006 RIKEN-BNL Research Center Workshop - BNL 12
The central detectors of the ALICE experiment
PHOtonSpectrometer
-0.12< < 0.12azimuth 100°
active area 8 m2
02/2006 RIKEN-BNL Research Center Workshop - BNL 13
The central detectors of the ALICE experiment
High-MomentumParticle Identification
Detector
PHOtonSpectrometer
Time ProjectionChamber
Inner Tracking System
Time Of Flight
Transition-Radiation Detector
02/2006 RIKEN-BNL Research Center Workshop - BNL 14
Fiducial volume and reconstruction strategies
Standard / extended fiducial volume leading to high purity / efficiency for
strange particle reconstruction
02/2006 RIKEN-BNL Research Center Workshop - BNL 15
Simulation of hyperons in Pb+Pb
Expected invariant mass distribution for 300 central HIJING simulated events.
R. Vernet et al. ALICE Internal Note 2005 - 042
Expected raw spectra extrapolated to 107 central events (first year Pb+Pb data).
02/2006 RIKEN-BNL Research Center Workshop - BNL 16
PID Range of ALICE at mid−rapidityEstimates as in the Physics Performance Report Vol.II
for one year of Pb+Pb data-taking (central events)
107 central Pb+Pb events
02/2006 RIKEN-BNL Research Center Workshop - BNL 17
Hadronization via coalescence at LHC energiesFries and Müller, EJP C34, S279 (2004)
Calculation implies assumption on transverse radial flow extrapolation
Amplitude for mixed ratio is the same at LHC than for RHIC but the limit is pushed to higher pT
Probing baryon/meson differences at LHC energies implies PID over a large pT range and ALICE is perfectly designed for this.
But first ALICE data will be elementary collisions check magnitude of this behaviour then assume
coalescence mechanisms if needed.
02/2006 RIKEN-BNL Research Center Workshop - BNL 18
Simulation of hyperons in p+p
Reconstruction rates for different multiplicity regimes (soft / hard)
L. Gaudichet et al. ALICE Internal Note 2005 - 041
Expected raw spectra extrapolated to 109 events (first year p+p data).
Baryon over meson ratio in p+p collisions (gluonic baryon junction).
02/2006 RIKEN-BNL Research Center Workshop - BNL 19
Mixed ratio @ UA1: p+p @ 630 GeV
Extracting mixed ratio from 1996 UA1 strange particle data
Ratio vs pT already surprisingly high in p+p data at high energies
02/2006 RIKEN-BNL Research Center Workshop - BNL 20
Hard/soft/min.bias spectra @ CDF: p+p @ 1800 GeV Extrapolation using CDF strange particle publication: PR D72 (2005) 052001
Main difference between preprint and final publication is a comparison with PYTHIA 6.216
After PYTHIA tuning with pions, the bottom line is min. bias spectra is close but K0s is slightly
overestimated
02/2006 RIKEN-BNL Research Center Workshop - BNL 21
Mixed ratio @ CDF: p+p @ 1800 GeV
Extracting mixed ratio from 2005 CDF strange particle data
Ratio vs pT slightly lower but compatible within errors
02/2006 RIKEN-BNL Research Center Workshop - BNL 22
Mixed ratio using PYTHIA: p+p @ 14 TeV
This feature is not observed in default PYTHIA at 14 TeV:
1) Going from LO to NLO may help getting the magnitude;
2) Other ingredients may be needed to get the shape.
Simulation used for PPR analysis by L. Gaudichet
Extrapolation of the main behaviours from RHIC, UA1 and
CDF data is currently being investigated.
02/2006 RIKEN-BNL Research Center Workshop - BNL 23
Conclusion
Using strangeness as a powerfull probe at LHC energies
with the PID capabilities of the ALICE experiment
a) equilibrium vs non-equilibrium scenariob) kinetic freeze-out of multi-strange particlesc) hadronization and coalescence validity at LHC
strange particles (specific probes and PID) !
First measurements of strange particles in p+p to extract:
1) interesting for baryon creation mechanisms2) references for Pb+Pb mandatory
WARNING: minimum bias trigger for p+p !