CASTORCentauro And Strange Object Research

Strangelet hunt at CMS

Panos KatsasUniversity of Athens, Nuclear & Particle Physics Department

for the CASTOR collaboration

Adana, Athens, Krakow, Demokritos, INR, Ioannina, MSU, Northeastern

COSMIC QCD II, Skopelos, 25/09-1/10 2005

Outline

● CASTOR detector description● Motivation & Physics● Experimental data & model description of

strangelets● Monte Carlo results (CNGEN, HIJING)● Simulations results & CASTOR● Strangelet analysis● Summary

CA STOR Review 26/ 05/ 05 A postolos D . Panagiotou

1

Reading Unit

Air-core Light Guide

PMTs

Beam

Active volumeW/ Q-plates Sampling Units

W-plate (octant)

Q-plate (semi-octant)

CASTOR CALORIMETER CONCEPTUAL DESIGN- Cerenkov light is generated inside the quartz plates as they are traversed by the fast charged particles in the shower (shower core detector) developing in tungsten absorber - Azimuthal and longitudinal sampling sufficient for a study of structures in longitudinal development of cascades

- High depth for detection of strongly penetrating objects

EM = 2RU (~ 28 X0) HAD = 16 RU (~10 Λ I )

RU ~ 7 Sampling U ~ .544 Λ

I ~ 14 X0

(16 azimuthal sectors)

Detectors near beamline: Forward Physics in p+p, p+A, A+A

TOTEM T2IP

TOTEM T1HF

ZDC @ 140 m

CASTOR

•Hermetic coverage up to || ~ 6.6•Zero degree neutral energy•Physics: Centrality, Low-x, Limiting fragmentation, Strangelets, DCC

Option 2 (preferred)

CASTOR

5.31 < < 6.84

Inner radius ~ 38 mm

Outer radius ~ 135 mm active

Outer radius ~ 280 mm total

T2 Tracker

5.32 < < 6.71

CMS Very-Forward Region

HF

3 < < 5.3

EM - PROTOTYPE W-PLATES + Q-

FIBRE / PLATES

~ 20 Xo

H CASTOR A L

CASTOR PROTO BEAM TEST 2003

5mm W + 2mm Q H

3mm W + 1.5mm Q EM

Octant

Semi-Octant

CASTOR PROTO II

4-APDs

4-APDs

4-APDs

4-APDs

4(6)-APDs

APDs PMT

CASTOR PROTO II

2004 Test – Beam Results

CENTAURO RELATED PHENOMENAat Mt Chacaltaya (5200 m) and Pamir (4300 m)

CENTAURO SPECIES:

Abnormal hadron dominance (in N and E), high pT, low multiplicity

● CENTAUROS of original type (5 “classical” Chacaltaya + over a dozen others) Nh ~ 100, PT ~ 1.75 GeV/c

● MINI-CENTAUROS

● CHIRONS

STRONGLY PENETRATING COMPONENT:

cascades, clusters, halos, frequently accompanying hadron-rich events

Review: E.G.-D. Phys. Part. Nucl34(2003)285

STRONGLY PENETRATING CASCADES in Pb CHAMBERSSTRANGELETS?

Cascades pass through the chamber practically without attenuation and revealed many-maxima character with small distances between humps

First observation:Krakow group,17th ICRC, 19812 exotic cascades in Centauro-like event

Other eventsArisawa et al.,Nucl. Phys. B424(1994)241

60 cm Pb~3.6 Λ intEnd of usual hadroniccascade ~1.5 Λint

Long penetrating hadronic component in CR events

(Strangelet ??)

3.6 λI

3.2 λI

3.6 λI

Hadron 1.5 λI

Hadron

CENTAURO FIREBALL EVOLUTION

56A + 14N

u, d g s s

QUARK MATTER FIREBALL

in the baryon-rich fragmentation region

High b suppresses production

of (u u) , (d d), allowing for g s s

K+, K0 carry out:

strangeness, positive charge, entropy

CENTRAL COLLISION

at the top of the atmosphere

Ep ~1740 TeV

u, d,s

K+

K 0

(u s)

(d s)

u

s

d

(pre-equilibrium) KAON EMISSION

SQM FIREBALL

EXPLOSION

StrangeletHG

...

HG

B ¼ < 190 MeV B ¼ > 190 MeV

Stabilizing effects of s quarkslong lived state

~75 non strangebaryons+ strangelet

(A ~ 10-15)

Strangenessdistillationmechanism:

C. Greineret al., Phys. Rev. D38

(1988)2797

Estimated for LHC Centauros:

• Energy density ε ~ 3 - 25 GeV/fm 3, • Temperature T ~ 130 - 300 MeV• Baryon chemical potential µb ~ 0.9 - 1.8 GeV/fm3

Possible STRANGELET FORMATION

CNGEN Centauro generator

+Strangelet formation

Stable strangelet interaction in CASTORMC-algorithm

Strangelet is considered with radius:

Mean interaction path:

Passing through the detector strangelets collide with W nuclei: Spectator part is continuing a passage; Wounded part produces particles in a standard way.

Particles produced in successive interaction points initiate a development of electromagnetic-nuclear cascades. Process ends when strangelet is destroyed.

E. Gładysz, Z. Włodarczyk, J. Phys. G23(1997)2057

31

23223s

str31

0

mμμπ

2a12

A3πArR

231

str03

1

W

NWWstr

ArA1.12π

mAλ

nstrstr NAA'

Code implemented in CMS environment

MULTIPLICITY in CASTOR’s acceptance

CENTAURO HIJING

Low multiplicity High multiplicity mostly baryons + kaons dominated by pions

Simulations with CNGEN (S. . Sadovsky et al..,Phys. Atom. Nucl. 67(2004)396 )

N = 58 N = 2300

5.3 < < 6.8

Probability of CENTAURO and STRANGELET detection

1.74cmCASTOR

~70 % of Centauro fireball decay products and substantial part of created strangelets are within CASTOR’s acceptance

Even very high energy strangelets (E ~ 30 TeV) are expected to be produced

5.3 << 6.8T=300 MeV

Ewa Gladysz

CASTOR

Probability of CENTAURO and STRANGELET detection

CASTOR

� ~65 % of Centauro fireball decay products and substantial part of strangelets are within CASTOR’s acceptance

� Even very high energy strangelets (E ~ 20 TeV) are expected to beproduced

5.3 < < 6.8T=250 MeV

Simulation results& CASTOR

HIJING Pb + Pb Event (background)

E ~ 130 TeV ~ 8 TeV/sector

<N> ~ 100/sector

CASTORCASTOR

Energy distribution in CASTOR

HIJING Strangelet in one sector

Energy in sectors Energy in RU’s Energy in sectors Energy in RU’s

Strangelet simulations in the CMS environment

(OSCAR)

Geometry configuration:

1 layer: 5 mm W + 2 mm quartz plate ~2.37 X0

1 SU = 7 layers per readout unit

16 (in x 18 (in z) readout channels

Total depth: ~300 X0, 10.5 int

EVEN LOW ENERGY STRANGELETS (~5 TeV) ARE APPARENTLY SEEN ABOVE THE BACKGROUND !

300 X0

Strangelet identification & Analysis

Strangelet signatures

Azimuthal asymmetryIn energy deposition

Longitudinaltransition curves

sd

iE

EE

Event-by-event analysis Analysis procedure in 2 steps:

average distribution

energy distribution per RU

Large magnitude offluctuations manifestabnormal transition curves

nsfluctuatio

HIJING + strangelet

HIJING

HIJING+strangelet1 2 3 4

5 6 7 8

9 10 11 12

13 14 15 16

Transition curves & fluctuations

Fluctuations in energy distribution

RU’s

Sector containing strangelet

Analysis results: IEstr = 7,5 TeV Estr = 10 TeV

EM-cutonly H-section

EM+H section

sector containingstrangelet

Two Stage Construction & Implimentation

STAGE I STAGE II

STAGE I

STAGE II

Reducing the number of RU’s16x18 channels 16x9 channels

Conclusions

● CASTOR is the experimental tool for strangelets ● Strangelet detection through measurement of:

– extreme imbalance between the hadronic and electromagnetic component (multiplicity & energy)

– non-uniform azimuthal energy deposition– penetrating objects beyond the range of normal

hadrons, abnormal longitudinal energy deposition pattern

CENTAURO I

Observed:Energy ~ 231 TeV 7 cascadesin upper chamber

43 cascades in lower chamber

Lattes,Fujimoto, Hasegawa, Phys. Rep. 65, 151 (1980)

Ohsawa, Shibuya, Tamada, Phys.Rev.D70,074028(2004)

Energy in CASTOR reading channels

torzID ule sec118 mod1 Continuous numbering schemes:16 x 18 = 256 channels uleztorID mod2 1sec16

HIJING Strangelet

ID2ID1 ID1 ID2

Analysis results: II

Strangelet in two sectors

Ε1 ~ 3.3TeV

E2 ~ 4 TeV

Estr = 7,5 TeVSectors withstrangelet

~ 14% of strangelets deposit their energy in two sectors

A=15, E=7.5 TeVA=10, E=5 TeV 60 pions, 1TeV each