ALICE Run 3 and ALICE3
Daiki Sekihata (Center for Nuclear Study, the University of Tokyo)
29.March.2024, TCHoU workshop in QNM, Tsukuba

LHC schedule

LS2: O2 upgrade

We are here.

LS3: ITS3 upgrade (silicon tracker)

ALICE329.March.2024

Daiki Sekihata (CNS, U.Tokyo)

2

ALICE detectors in LHC Run3

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

3

ALICE Run3
• Highest collision energy √sNN = 5.36 TeV• dNch/dη ~ 2000 in central collisions• Upgrade during LS2- GEM TPC (fast readout)- ITS2 (vertexing resolution)- Online-Offline (O2) reconstruction

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

4

30

Recorded: 28.2 pb-1

25201.6

ALICE Performance, 2023

1.4

Pb−Pb, sNN = 5.36 TeV

12Recorded: 1535.5 µb−1

101.2
810.8

15

Number of collisions (B)ALICE Performance, Run 3, pp, s = 13.6 TeV

Integrated luminosity (nb−1)

Integrated luminosity, pb-1

Integrated luminosity in ALICE

60.6
4

100.4
520.20002 Jul 22

ALI−PERF−558527

01 Oct 2231 Dec 2202 Apr 23

02 Jul 23005 Oct

ALI−PERF−564518

12 Oct19 Oct26 Oct• 28.2 pb-1 in pp at 13.6 TeV ~ 2T collisions• 1.54 nb-1 in PbPb at 5.36 TeV ~ 12B collisions

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

5

800

TOF βdE /dx (arb. units)

PID performance in Run3
ALICE Performance
Run 3 pp, s = 13.6 TeV
9524.3 × 10 events

700

ALEPH Bethe-Bloch fit

600

1.1

10.9

500
0.8

400
0.7

300

0.6200

ALICE Performance

1000−3
ALI−PERF−542850

0.5−2−101230.40p / Z (GeV/ c )Run 3, pp s = 13.6 TeV

0.511.522.533.5p (GeV/c )ALI-PERF-537607• Clear separation of e/π/K/p/d/t/He with TPC dE/dx• Clear separation of e/π/K/p with TOF β

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

6

Charmed hadrons in Run 3−3

ALICE Performance
20 pp, s = 13.6 TeV
offline trigger

15

Normalised counts / 4 MeV/ c 2

Normalised counts / 4 MeV/ c 2−3×100

D → K−π+ and charge conj.
p > 1 GeV/c×10DataBackgroundTotal fit function
2015

1.85

1.91.95
22M (Kπ) (GeV/ c )×10−32015+1.75

Normalised counts / 4 MeV/ c 2

Normalised counts / 4 MeV/ c 2

1.8+− +Ds → φπ → K K π+ and charge conj.
p > 1 GeV/cT

1.85
ALI−PERF−545790

29.March.2024

1.9

1.95
22
M (KKπ) (GeV/ c )• PromisingTT

1.75+D → K−π+π+ and charge conj.
p > 1 GeV/c• Clear peaks of D mesons and Λc+• Results from 290B events recorded in2022

1.8

1.85

1.9
1.95
M (Kππ) (GeV/ c 2)

×10−3222018+−16 Λc → pK π+ and charge conj.
p > 2 GeV/cT

2.2

2.25

2.3

2.35
2M (pKπ) (GeV/ c )Daiki Sekihata (CNS, U.Tokyo)

7

×103
180

ALICE performance

160pp s = 13.6 TeV

140

J/ ψ , ψ (2S) → e e0.0 < p < 16.0 GeV/c , | y | < 0.9

same event unlike-sign+

mix event unlike-sign

T

120
100
80

Counts per 20 MeV/c 2

Entries per 40 MeV/ c 2

Charmonia in Run 3
106

ALICE Preliminary, pp, s = 13.6 TeV+Inclusive J/ψ, ψ(2S) → µ µ-, 2.5 < y < 4
p < 20 GeV/cDataTFitJ/ψψ(2S)
Background

105

104

60
40103

202.5

raw countsS ) = 462.42
S + B J/ψ= 19.19( S )S + B ψ(2S)(105ALI-PREL-558674

3

3.5

4

4.5mµµ (GeV/ c 2)

CB2 + residual bkg
residual bkg• Clear J/ψ and ψ(2S) peaks in both dielectron anddimuon channels

104

2.2

2.4

ALI-PREL-548566

29.March.2024

2.6

2.8

3

3.2

3.4

3.6

3.8

4

mee (GeV/c 2)
Daiki Sekihata (CNS, U.Tokyo)

8

ALICE Performance

600
500
400pp, s = 13.6 TeV

Unlike signΥ (nS)→e+e-, |y | < 0.9

Fit, total

0.0 < p T < 25.0 GeV/ cFit, combinatorial bkg

Counts per 20 MeV/c 2

Entries per 100 MeV/c 2

Bottomonia in Run 3
1400

ALICE Performancepp, s = 13.6 TeV

1200

2.5 < y < 4, Υ (nS) → µ µ

1000

MCH+MID

DataFitΥ (1S)
Υ (2S)
Υ (3S)
Background+ -p < 20 GeV/c
800

T300
600

200

400

100

200350
Opposite sign - Combinatorial bkg

300

Υ (1S)200

Υ (2S), Υ (3S)

100
50
6

ALI-PERF-549380

29.March.2024

7888.599.51010.5

11mµ+µ11.5

122- (GeV/ c )• First bottomonia peaks with dielectron channel inALICE- 500B events analyzed• Υ(1S), Υ(2S), Υ(3S) peaks

150

07.5

ALI−PERF−549856

Fit, signal

250

07

91011122mee (GeV/c )Daiki Sekihata (CNS, U.Tokyo)

9

10−1

2 −1
1/N ev dN raw
ee /dm ee (GeV/c )2 −1
1/N ev dN raw
ee /dm ee (GeV/c )Dielectrons in Run3
ALICE Performance10−2pp s = 13.6 TeV
p10−3T,e> 0.2 GeV/ c , |ηe| < 0.810N ev = 5.79 × 10

10−410−510−610−2−310

ALICE Performance

DCA3Dee integrated

pp s = 13.6 TeVDCAee > 2 σpT,e3D> 0.2 GeV/ c , |ηe| < 0.83DDCAee < 0.5 σ10N ev = 5.79 × 10
10−410−510−610−710−710−810−810−910−100246810−9100.5

11.522.5m ee (GeV/c )ALI-PERF-548516

33.5422m ee (GeV/c )ALI-PERF-549823• Clear π0, η, ω/ρ, φ, J/ψ, ψ(2S), and Υ signals and correlated HF→ee continuum• DCA analysis based on different life time of emission sources (Distance of Closest Approach)- Prompt (mesons and possible thermal radiation)- Non-prompt (correlation HF→ee, cτ~150μm for D mesons, 400μm for B mesons)29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

10

80

−51060Counts / 4 MeV/c 2100

ALICE Performance Photon Conversion Method (γ → e+e−)
pp, s = 13.6 TeV |ηγ | < 0.9

Nγ /Nevconversion point Y (cm)Photon conversions
×103
14

ALICE Performancepp, s = 13.6 TeV
1.0 < p< 1.2 GeV/ cT,γ γ12

π0 → γ γ , PCM-PCM
signal + backgroundmixed-event backgroundsignalfit to signal

10402010−6806−20−40

10−7−60

42−80−100−100 −80 −60 −40 −20
ALI−PERF−559129

0 20 40 60 80 100
conversion point X (cm)10−800.06

0.08

ALI−PERF−559133

0.1

0.12

0.14

0.16

0.18

0.2
0.22m γ γ (GeV/ c 2)

• Critical technique to measure photons at low pT.
• ITS, TPC, and their support structures are visible.
• Clear reconstruction of π0→γγ29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

11

ALICE3• Project after 2035
• Advanced silicon technology- High-rate data acquisition- Precise vertexing with retractable tracker- Strong particle identification at low pT

LoI : arXiv:2211.02491
29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

12

ALICE3 : Main physics goals – 2 pillars –• Electromagnetic probes- Thermal radiation- Pre-equilibrium radiation- Chiral symmetry restoration• Heavy flavors- Multi-charmed hadrons- Beauty baryons beyond Λb0- XXXXAgain, high statistics and precise vertexing are crucial for both topics.

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

13

Strangeness tracking• Retractable tracker allows us to track hyperons, so-called “strangeness tracking”.
• Key to reconstruct multi-charmed hadrons
29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

14

Multi-charmed hadronsπ• Precise primary andsecondary vertexing• Necessary for multicharmed hadrons andexotic hadrons.

ALI-SIMUL-510941

ALI-SIMUL-510958

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

15

1/ N ee dN ee/DCA ee (σ)-1Electromagnetic radiation
ALICE 3 Study
cc → ee (ITS1: pp Pythia6, 7 TeV, pT,e> 0.4 GeV/ c )cc → ee (ITS2: 0-10% PbPb HIJING, 5.02 TeV, p
cc → ee (ALICE 3: pp Pythia8, 14 TeV, p

1T,eT,e> 0.2 GeV/ c )> 0.08 GeV/ c )prompt × 0.7 (ALICE 3)

10−110−2024681012DCAee (σ)

ALI-SIMUL-540877• Determine early stage of the collision- e.g. dN/dmee ∝ exp(-mee/T) in 1.1 < mee < 2.0 GeV/c2.
• Electrons from charmed hadrons are main background.
- precise vertexing is necessary.
29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

16

Direct photon HBTPRC 102, 024915 (2020)• Size of emission source (size of QGP)• Disentangle direct photon puzzle- large yield (early emission) and large v2(late emission) of thermal photons are notunderstood.
• High-kT diphoton pair provides insight on early stage ofspace-time evolution

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

PLB 837 (2023) 137647
arXiv:2308.09747
17
arXiv:2403.04846

Summary• ALICE upgrade is successfully done during LS2.
• ALICE recorded high statistics in 2022 and 2023.
- 28.2 pb-1 in pp at 13.6 TeV- 1.54 nb-1 in PbPb at 5.36 TeV• Nice performance and physics preliminary plots from Run 3• ALICE3 project with advanced silicon technology- retractable tracker in beam pipe
- PID with TOF, RICH
- 2 main pillars : EM probes and HF hadrons

29.March.2024

Daiki Sekihata (CNS, U.Tokyo)

18