Alexander Schmah - GSIINPC 2007/06/04

Hadron identification via energy loss measurements of the HADES multi-

wire drift chambers

Alexander Schmah, Jochen Markert, Christian Müntz,Manuel Lorenz and Joachim Strothfor the HADES collaboration

Alexander Schmah - GSIINPC 2007/06/04

HADES Setup

Explosion view Side view

High Acceptance Di-Electron Spectrometer HADES @ SIS/GSI

はです

Alexander Schmah - GSIINPC 2007/06/04

PID via TOF/TOFino

TOFino (18° < < 45°) TOF (44° < < 88°)

psTOFino 400 psTOF 150

Alexander Schmah - GSIINPC 2007/06/04

TOFino Multiplicity

TOFino• only 4 pads/sector

Solution: RPC detector,available in 2008

But: Ar+KCl @ 1.756 AGeV,September 2005 data

Solution: MDC dE/dxinformation

65 % multi hit probability

1.5 m

Alexander Schmah - GSIINPC 2007/06/04

Multi wire drift chambers (MDC)

• 6 layers per module• Low mass concept• • Total number of clusters per cm 80

40 105/ Xx

drift cell

• dE/dx depends on the Geometry of a track in a 3D drift• Parametrization in , distance to wire and MDC type

5-10 mm

Ar-C4H10

He-C4H10

Alexander Schmah - GSIINPC 2007/06/04

ToT-dE/dx Simulation

Schematic simulation of Time-over Threshold

nonlinearbehaviour

MDC ASD8 readout chips +TDC can measure ToT*

* The HADES tracking system (NIM Phy. Res. A 535 (2004) 242-246)

Alexander Schmah - GSIINPC 2007/06/04

Correction strategy

Strategy for correction

• Select protons in TOF region• Calculate dE/dx via Bethe-Bloch and measured momentum• derive correction functions

Alexander Schmah - GSIINPC 2007/06/04

ToT-dE/dx

distance to angle wire

Correction functions

Alexander Schmah - GSIINPC 2007/06/04

Corrected MDC dE/dx

MDC I MDC II MDC III MDC IV

Truncated mean is calculated from all measurements of a track

particle track

Alexander Schmah - GSIINPC 2007/06/04

Proton Cut

MDC dE/dx - proton cut TOF mass spectrum

K+

p- +

Alexander Schmah - GSIINPC 2007/06/04

Pion Cut

MDC dE/dx - pion cut TOF mass spectrum

K+

p- +

Alexander Schmah - GSIINPC 2007/06/04

Kaon Cut

MDC dE/dx - kaon cut TOF mass spectrum

K-

K+

p- +

Alexander Schmah - GSIINPC 2007/06/04

0SK

p

Preliminary results (40 % of total statistics)

0SK

p

Alexander Schmah - GSIINPC 2007/06/04

KK

Hint for a -signal @ 1.756 AGeV (NN threshold for = 2.59 GeV)

Preliminary results(40 % of total statistics)

MDC dE/dx• available for the full acceptance • directly used for hadron PID at high multiplicities• used for background reduction (K+, K-)• additionally used for e+,e- PID

Ar+KCl

Alexander Schmah - GSIINPC 2007/06/04

HADES Collaboration

G. Agakishiev8, C. Agodi1, A. Balanda3,e, G. Bellia1,a, D. Belver15, A. Belyaev6, A. Blanco2, M. Böhmer11, J. L. Boyard13, P. Braun-Munzinger4, P. Cabanelas15, E. Castro15, S. Chernenko6,

T. Christ11, M. Destefanis8, J. Díaz16, F. Dohrmann5, A. Dybczak3, T. Eberl11, L. Fabbietti11, O. Fateev6, P. Finocchiaro1, P. Fonte2,b, J. Friese11, I. Fröhlich7, T. Galatyuk4, J. A. Garzón15,

R. Gernhäuser11, C. Gilardi8, M. Golubeva10, D. González-Díaz4, E. Grosse5,c, F. Guber10, M. Heilmann7, T. Hennino13, R. Holzmann4, A. Ierusalimov6, I. Iori9,d, A. Ivashkin10, M. Jurkovic11, B. Kämpfer5, K. Kanaki5, T. Karavicheva10, D. Kirschner8, I. Koenig4,

W. Koenig4, B. W. Kolb4, R. Kotte5, A. Kozuch3,e, F. Krizek14, R. Krücken11, W. Kühn8, A. Kugler14, A. Kurepin10, J. Lamas-Valverde15, S. Lang4, J. S. Lange8, L. Lopes2, L. Maier11, A. Mangiarotti2, J. Marín15, J. Markert7, V. Metag8, B. Michalska3, D. Mishra8, E. Morinière13,

J. Mousa12, C. Müntz7, L. Naumann5, R. Novotny8, J. Otwinowski3, Y. C. Pachmayer7, M. Palka4, Y. Parpottas12, V. Pechenov8, O. Pechenova8, T. Pérez Cavalcanti8, J. Pietraszko4, W. Przygoda3,e,

B. Ramstein13, A. Reshetin10, M. Roy-Stephan13, A. Rustamov4, A. Sadovsky10, B. Sailer11, P. Salabura3, A. Schmah4, R. Simon4, S. Spataro8, B. Spruck8, H. Ströbele7, J. Stroth7,4, C. Sturm7,

M. Sudol4, A. Tarantola7, K. Teilab7, P. Tlusty14, M. Traxler4, R. Trebacz3, H. Tsertos12, I. Veretenkin10, V. Wagner14, H. Wen8, M. Wisniowski3, T. Wojcik3, J. Wüstenfeld5,

S. Yurevich4, Y. Zanevsky6, P. Zumbruch4

Alexander Schmah - GSIINPC 2007/06/04

Topology

• Topology of dE/dx as a function of MDC type, and distance-to-wire• 4 MDC types• 5 degree angle bins• 0.1 mm to 0.25 mm distance-to-wire bins

drift cell

Alexander Schmah - GSIINPC 2007/06/04

Multi wire drift chambers (MDC)

• Low mass concept• 6 layers per module

drift cell

Alexander Schmah - GSIINPC 2007/06/04

ToT-dE/dx Data I

Stragety

• Select protons in TOF region• Calculate dE/dx via Bethe-Bloch and measured momentum

Alexander Schmah - GSIINPC 2007/06/04

MDC dE/dx resolution

p-

+

%15%10 R

- +

p

Landaufit foreach slice

Alexander Schmah - GSIINPC 2007/06/04

Multi wire drift chambers (MDC)