Transcript ppt

Hot Quarks 2006
Strange Prospects for LHC energies
1. Strangeness at LHC energies
Extrapolations / Motivations
2. Strange probes with ALICE
Detector and Simulations
3. First p+p Collisions and beyond
First measures to target
Boris HIPPOLYTE for the ALICE Collaboration,
IPHC Strasbourg
Hot Quarks 2006 - Sardinia - 16/05/06
Wroblewski factor extrapolation to LHC energies
Wroblewski factor:
<ss >
λs  2
<uu >+<dd >
Extrapolation at the LHC
A+A ~0.45
p+p ~0.25
Data compilation using Becattini et al., PR C64 (2001) 024901, hep-ph/0002267 and references therein
Using thermal model description with corresponding system formalism
(canonical or grand-canonical), extrapolation is straightforward.
05/2006
Hot Quarks 2006 - Villasimius
2
Excitation functions of hyperons yields in A+A
dN/dy extrapolations at the LHC
for L : 10~30
for X : 3~6
for W : 0.4~0.7
Expected modifications
total multiplicity scaling
non-equilibrium scenario
05/2006
Hot Quarks 2006 - Villasimius
3
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 ]
Calculations from
Kraus et al., (Eq.)
Rafelski et al., (Non Eq.)
Expectations at the
LHC energies (eq.):
Tch ~170 MeV
mB ~1 MeV
Scenarii for gs
05/2006
Hot Quarks 2006 - Villasimius
4
Hadronization via coalescence at LHC energies
Fries and Müller, EJP C34, S279 (2004)
Calculation implies assumption on
transverse radial flow extrapolation
Probing baryon/meson differences at LHC
energies implies PID over a large pT range
and ALICE is perfectly designed for this.
05/2006
Amplitude for mixed ratio is the
same at LHC than for RHIC but
the limit is pushed to higher pT
But first ALICE data will be elementary collisions a
check magnitude of this behaviour then assume
coalescence mechanisms if needed.
Hot Quarks 2006 - Villasimius
5
The central detectors of the ALICE experiment
Transition-Radiation
Detector
High-Momentum
Particle Identification
Detector
-0.6< h < 0.6
azimuth 57.61°
active area 10 m2
Inner Tracking
System
Time Projection
Chamber
-0.9< h < 0.9
azimuth 2p
length 5 m
active volume 88 m3
-0.9< h < 0.9
silicon layers 6
pixel/drift/strip 2/2/2
cells(M) 9.84/23/2.6
area 0.21/1.31/4.77 m3
PHOton
Spectrometer
Time Of Flight
-0.9< h < 0.9
azimuth 2p
length 7.45 m
active area 141 m2
05/2006
Hot Quarks 2006 - Villasimius
6
Fiducial volume and reconstruction strategies
Standard / extended fiducial volume leading to high
purity / efficiency for strange particle reconstruction
W
Expected raw spectra extrapolated to 107
central events (first year Pb+Pb data).
05/2006
Hot Quarks 2006 - Villasimius
7
PID Range of ALICE at mid−rapidity
Estimates as in the Physics Performance Report Vol.II
for one year of Pb+Pb data-taking (central events)
107 central Pb+Pb events
05/2006
Hot Quarks 2006 - Villasimius
8
Baryon/Meson pT ratio in p+p @ 630 and 1800 GeV
Extracting mixed ratio from UA1 spectra (1996) and from CDF spectra (2005)
Ratio vs pT already surprisingly high in p+p data at high energies
05/2006
Hot Quarks 2006 - Villasimius
9
Extrapolations and PYTHIA: p+p @ 14 TeV
LHC extrapolation: “ATLAS tuning” min. bias and underlying event
simulation samples: 1M p+p events
Different sets of parameters (tuning) for LHC
energies:
a) extrapolation of Tevatron data (CDF tune A);
b) data for jets and high-pT phenomena;
Low pT description implies specific treatment
a) O.M.I (v6.2): different pars for und. event & min. bias
a first PYTHIA v6.2 description of soft domain @ LHC (different rescaling factor for und. event)
b) N.M.I in PYTHIA 6.3: multiple part-part int. (+ i/fsr)
05/2006
Hot Quarks 2006 - Villasimius
10
PYTHIA Baryon/Meson pT ratio: p+p @ 14 TeV
Ratios and differences between min. bias and underlying event description
Checking uncertainty for parameters energy
dependence:
PYTHIA authors’ suggestions : 2e~0.08 a 0.25
Comparison between ATLAS tuning and
underlying event description
Little light/strange flavor dependence in this region
Underlying event description needed/enough for
production of hadrons in intermediate pT region ?
05/2006
Hot Quarks 2006 - Villasimius
11
Recent extrapolation from the Les Houches Working Group
preprint hep-ph/0604120
Major evolutions for LHC extrapolation:
PYTHIA: v6.2 a v6.3
New multiple interaction (N.M.I) treatment
a part.-part. interactions and i/fsr
PDF: CTEQ5 a CTEQ6
main change in gluon distribution function
a visible at low Q2
Better but still missing a factor of ~2
wrt RHIC a UA1 a CDF extrapolations
a investigating NLO contribution, baryon
creation mechanisms (diquark, popcorn
scenario, and gluonic baryon junctions).
05/2006
Hot Quarks 2006 - Villasimius
12
Conclusion
Using strangeness as a powerfull probe at LHC energies
with the PID capabilities of the ALICE experiment
a) Equilibrium vs non-equilibrium scenario
b) Hadronization and coalescence validity at LHC
a strange particles (specific probes and PID) !
First measurements of strange particles in p+p to obtain:
1) Interesting for studying baryon production mechanisms
2) Constrains for underlying event description
3) Set references for Pb+Pb (mandatory)
WARNING: minimum bias trigger for p+p !
05/2006
Hot Quarks 2006 - Villasimius
13
Complementary slides
05/2006
Hot Quarks 2006 - Villasimius
14
Hard/soft/min.bias CDF spectra: 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 L spectra is close but K0s is slightly
overestimated
05/2006
Hot Quarks 2006 - Villasimius
15
Table of Parameters for v6.214
References: 6.215 / 6.400
6.215
6.4
Input
Page: Default=
PYPARS Switchs
MSTP(51)
MSTP(52)
MSTP(68)
MSTP(70)
MSTP(81)
MSTP(82)
MSTP(88)
MSTJ(1)
MSTJ(12)
(p196/205:D=7)
(p197/205 :D=1)
(p301/322: D=1/3)
(p/322: D=/1)
(p316/347: D=1)
(p317/348: D=1/3)
(p/350: D=1)
(p363/401: D=1)
(p364/402: D=2)
References: QEHwg05
AliPythia
Config.C
v6.214
ATLAS tune
OldUEr1
OldUEr2
OldUEr3
Simple Popcorn Advanced Popcorn
(+ATLAS)
(+ATLAS)
(p/320)
kCTEQ5L
1
1
4
1
4
1
4
1
4
2
1
3
PYPARS Parameters
PARP(67)
PARP(71)
PARP(82)
PARP(83)
PARP(84)
PARP(85)
PARP(86)
PARP(89)
PARP(90)
PARJ(1)
PARJ(18)
PARJ(81)
(p302/323: D=1/4)
(p302/323: D=4)
(p320/353: D=1.9/2.0)
(p320/354: D=0.5)
(p320/354: D=0.2/0.4)
(p320/354: D=0.33/0.9)
(p320/354: D=0.66/0.95)
(p320/354: D=1000/1800)
(p321/354: D=0.16)
(p368/406: D=0.1)
(p369/407: D=1)
(p299/319: D=0.29)
05/2006
(p371/409)
1
1.8
0.5
0.5
0.33
0.66
1000
0.16
4
4
2
0.5
0.4
0.9
0.95
1800
0.25
4
4
2
0.5
0.4
0.9
0.95
1800
0.16
(p372/410)
4
4
2
0.5
0.4
0.9
0.95
1800
0.08
Dx1.2
0.29
0.29
Hot Quarks 2006 - Villasimius
2
1
5
Dx2
0.19
0.29
16
Min. Bias CDF parameter sets: p+p @ 1800 GeV
05/2006
Hot Quarks 2006 - Villasimius
17
PYTHIA flavor dependence for Baryon/Meson pT ratio
05/2006
Hot Quarks 2006 - Villasimius
18
New multiple interaction description and
underlying event tuning parameters
New M.I: each interaction has its own set of isr and fsr
and not only the hardest parton-parton interaction
 hard parton-parton hard scattering cross section and
total rate given pQCD (validity?)
 hard ( pT min )  
s/4
pT2 min
d 2
dpT
2
dpT
divergent for pTmin  0
p Tmin assumed to increase with s just as total hadronic cross
section: power e ≈ 0.08
 s 
pT min ( s )  (1.9 GeV) 
2 
1
TeV


05/2006
Hot Quarks 2006 - Villasimius
ε
19
Table of Parameters for v6.326
References: 6.215 / 6.400
6.215
6.4
Input
Page: Default=
PYPARS Switchs
MSTP(51)
MSTP(52)
MSTP(68)
MSTP(70)
MSTP(81)
MSTP(82)
MSTP(88)
MSTJ(1)
MSTJ(12)
(p196/205:D=7) (->10042)
(p197/205 :D=1)
(p301/322: D=1/3)
(p/322: D=/1)
(p316/347: D=1)
(p317/348: D=1/3)
(p/350: D=1)
(p363/401: D=1)
(p364/402: D=2)
References: QEHwg05
AliPythia
Config.C
v6.326
Min. Bias
(p/320)
kCTEQ6L
2
1
2
1
4
NewUEr1
kCTEQ6L
2
1
2
1
4
NewUEr2
kCTEQ6L
2
1
2
1
4
NewUEr3
kCTEQ6L
2
1
2
1
4
2
1
3
PYPARS Parameters
PARP(67)
PARP(71)
PARP(82)
PARP(83)
PARP(84)
PARP(85)
PARP(86)
PARP(89)
PARP(90)
PARJ(1)
PARJ(18)
PARJ(81)
(p302/323: D=1/4)
(p302/323: D=4)
(p320/353: D=1.9/2.0)
(p320/354: D=0.5)
(p320/354: D=0.2/0.4)
(p320/354: D=0.33/0.9)
(p320/354: D=0.66/0.95)
(p320/354: D=1000/1800)
(p321/354: D=0.16)
(p368/406: D=0.1)
(p369/407: D=1)
(p299/319: D=0.29)
05/2006
Simple Popcorn Advanced Popcorn
(+Min. Bias)
(+Min. Bias)
(p371/409)
2.3
0.5
0.5
0.9
0.95
1800
0.2
2.6
0.5
0.3
0.9
0.95
1800
0.24
2.6
0.5
0.3
0.9
0.95
1800
0.16
(p372/410)
2.6
0.5
0.3
0.9
0.95
1800
0.08
Dx1.2
0.29
0.29
Hot Quarks 2006 - Villasimius
2
1
5
Dx2
0.19
0.29
20
PDF comparison CTEQ6 vs. CTEQ5
J. Pumplin et al., preprint hep-ph/020195
05/2006
Hot Quarks 2006 - Villasimius
21
Extrapolations for LHC comparison: ATLAS tuning vs.
Les Houches working group Min.bias tuning
preprint hep-ph/0604120
05/2006
Hot Quarks 2006 - Villasimius
22