Ahren Sadoff CESR/CLEO Orientation Seminar Dec. 11, 12, 2006 dE/dx in CLEO Bethe Block Equation...

Ahren Sadoff

CESR/CLEO Orientation Seminar Dec. 11, 12, 2006

dE/dx in CLEO

• Bethe Block Equation ----- Depends only on β

• Defining the dE/dx variables

• Resolution

• The Corrections• Hit level

• Run level

• Track level

• Hadronic Separation

Particle ID using dE/dx

The Bethe Block Equation

dE/dx = (DZρ/A)1/β2[ ln(2meγ2β2c2/I) – β2 – δ/2]

Note:

• For low values of β: dE/dx ~ 1/β2

• For relativistic values of β: dE/dx ~ ln(γβ)2 ; “relativistic rise”

I = Average Ionization Energy

δ ~ lnγ2 for β ~ 1; “density effect” , saturates dE/dx

Ahren Sadoff


dE/dx vs βγ and Momentum

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The Landau distribution of the total energy loss across a gas volume. Note the long Landau tail on the distribution.

Resolution (σr)

σr ~ N-0.43

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Wire by Wire Gain Correction

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Path length and Entrance Angle Correction

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Atmospheric Pressure Correction (run level)

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Dip Angle Saturation (track level)

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Ahren Sadoff


dE/dx vs momentum

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K-π Separation

at P ≈ 2 GeV/c, K/π separation is ≈ 2σ

CBX 05-43 Pion and Kaon Identification Efficiencies for CLEO-c I. Brock, R. Briere

Ahren Sadoff


Ahren Sadoff CESR/CLEO Orientation Seminar Dec. 11, 12, 2006 dE/dx in CLEO Bethe Block Equation...

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