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Searching for Strange Quark Matter with the CMS/CASTOR Detector at the LHC

Searching for Strange Quark Matter with the CMS/CASTOR Detector at the LHC Apostolos D. Panagiotou, University of Athens for the CMS/CASTOR Group http://cmsdoc.cern.ch/castor /.

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Searching for Strange Quark Matter with the CMS/CASTOR Detector at the LHC

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  1. Searching for Strange Quark Matter with the CMS/CASTOR Detector at the LHC Apostolos D. Panagiotou, University of Athens for the CMS/CASTOR Group http://cmsdoc.cern.ch/castor/ V International Conference on PERSPECTIVES IN HADRONIC PHYSICS Particle-Nucleus and Nucleus-Nucleus Scattering at Relativistic Energies ICTP 22-26 May, 2006

  2. Outline • CASTOR Calorimeter at CMS • Exotic Events in Cosmic Rays • Phenomenological Models & MC Simulations • “Strangelet” Identification Analysis • CASTOR Prototypes - Beam test Results • Summary

  3. CASTOR Calorimeter at CMS

  4. CMS Forward Detectors CASTOR 5.2 < η < 6.6

  5. CASTOR Calorimeter Segmentation: 16(azimuth) x 14( in depth) = 224 channels Stage II Stage I

  6. CASTOR Calorimeter Stage II 16x4 = 64 Channels Stage I PMT W/Q plates 16x10 = 160 Channels Air-core Light Guide subtending 5 W/Q plates H section 10.3λΙ EM section 20 Xo

  7. Exotic Events in Cosmic Rays

  8. 61 mm Pb Typical Emulsion / Lead Chambers

  9. STRONGLY PENETRATING COMPONENT cascades, clusters, halos, frequently accompanying CR hadron-rich events. ADP, Zeits. Phys. A- Atomic Nuclei 333(1989)355 E.G.-D. Phys. Part. Nucl34(2003)285 Exotic Cosmic Ray Events CENTAURO SPECIES Abnormal hadron dominance (in N and E), high pT, low multiplicity • CENTAURO of original type (5 “classical” Chacaltaya + over a dozen others) Nh ~ 100, pT ~ 1.75 GeV/c • MINI-CENTAUROS • CHIRONS

  10. Hadron – Rich CR Events Homogeneous thick lead chamber Centauro Normal

  11. (Strangelet ?) 1.5 λI Hadron limit 3.6 λI Measurement settings: 100 μm shower core diameter  threshold ~ 3 TeV 3.6 λI 3.2 λI Hadron limit

  12. Phenomenological Models MC Simulations

  13. Estimates for Centauro at LHC • Energy density ε ~ 3 - 25 GeV/fm 3, • Temperature T ~ 130 - 300 MeV • Baryo-chemical potential µb ~ 0.9 - 1.8 GeV/fm3 CNGEN Centauro & Strangelet Generator anti-  Phys. Rev. D45(1992)3134Astroparticle Phys. 2(1994)167 Astroparticle Phys. 13(2000)173 Phys. Atom. Nucl. 67(2004)396

  14. Conditions for DQM-bag Stability Pqg = B Minimization of Bag energy (dE/dR = 0) in spherical DQM distribution with radius R and Nq massless quarks. Pressure of (u,d) quark-gluon plasma Pqg = (8/45)π2Τ4 +μq2Τ2 + μq4/2π2= (2.034Νq/4π)(1/R4) = B For CR Centauro (μq~ 600 MeV, T ~ 130 MeV, Nq ~ 225) R = roNb1/3 ~ 1.43 fm  ro = 0.34 fm (~ ro ‘collapsed’ nucleus) Astroparticle Phys.13(2000)173

  15. SQM: “Strangelet” Neutron Star QCD true Ground State

  16. StableStrangelet interaction in CASTORMC-algorithm Strangelet is considered with radius: Mean interaction path: Strangelets passing through the detector collide with W nuclei: Spectator part is continuing its passage. Wounded part produces particles in a standard way. Particles produced in successive interactions initiate electromagnetic-nuclear cascades. Process ends when strangelet is destroyed. E. Farhi, R. Jaffe, Phys.Rev.D30(1984)2379; M. Berger, R. Jaffe, Phys.Rev.C 35(1987)213, G.Wilky, Z.Wlodarczyk, J.Phys.G22(1996)L105; E. Gładysz, Z. Włodarczyk, J.Phys.G23(1997)2057 The rescaled r0 is determined by the number density of the strange matter: n = A/V = (1/3)(nu+nd+ns) where ni=- ∂Ωi/∂μi; Ω(mi,μi,αs), taking into account the QCD O(αs) corrections to the properties of SQM. s s s

  17. CASTOR Geometry configuration 1 layer: 5mm W+2mm quartz plate ~2.37 X0 1 RU = 7 layers per readout unit 16 (in  x 18 (in z) readout channels Total depth: ~300 X0, 10.5 Λint LOW ENERGY STRANGELETS (~5 TeV) MAY BE SEEN ABOVE BACKGROUND 300 X0 MC - Stable Strangelet in CASTOR P. Katsas HIJING Depth HIJING

  18. Strangelet Identification Analysis P. Katsas

  19. CASTOR Calorimeter Segmentation 14 Sections/Sector (longitudinal) 16 Sectors (azimuthal)

  20. HIJING Pb+Pb Event at √s = 5.5 TeV η GeV Etot ~ 130 TeV ~ 8 TeV/sector N < 100/sector η GeV ICTP/ Apostolos D. Panagiotou

  21. Total Energy Distribution in Sectors - HIJING Energy ICTP/ Apostolos D. Panagiotou Calorimeter Depth (RUs)

  22. Total Energy in Sector Energy in RU Total Energy in Sector Energy in RU HIJING Strangelet in one sector Energy distributions in CASTOR Average of 16 Sectors A = 15 E = 7.5 TeV <E> Energy (Depth) RU Sector (Depth) RU Sector

  23. Strangelet signatures Azimuthal asymmetry in energy deposition Longitudinal transition curves energy distribution per RU average distribution Large magnitude of energy fluctuations in RUs manifest abnormal transition curves Strangelet identification & Analysis • Event-by-event analysis • Analysis procedure in 2 steps: <E> = mean energy in sectors (i = 1 – 16 sectors)

  24. Analysis Results w/t background Estr = 10 TeV Estr = 7.5 TeV σE 3σ sector containing Strangelet + HIJING sectors containing HIJING Pb+Pb σfluctuations EM-cut only H-section EM+H section ICTP/ Apostolos D. Panagiotou

  25. Prototypes - Beam test Results L. Gouskos CMS Reports NIM publications

  26. CASTOR Proto I Beam Test

  27. CASTOR Proto II Beam Test 4(6)-APDs 4-APDs 4-APDs 4-APDs 4-APDs APDsPMT

  28. Energy Resolution - Electrons

  29. Energy Resolution - Hadrons

  30. SEMI-OCTANT GEOMETRY PROJECTION Ee = 200 GeV

  31. Spatial X-scan – Electrons Width of Shower σΕΜ = 1.9 mm

  32. Spatial X-scan – Pions Width of Shower σH = 5.3 mm

  33. Summary • CASTOR is the experimental tool for ‘Centauro’ and ‘Strangelet’ search in the forward rapidity at CMS • Identification through measurements of: • Extreme imbalance between hadronic and electromagnetic energy. • Non-uniform azimuthal energy deposition. • Penetrating objects beyond the range of normal hadrons  abnormal longitudinal energy deposition pattern. Observation of Centauro and (meta) stable SQM will have significant implications for QM-Physics and Astrophysics.

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