Some Slides for Michele

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Some Slides for Michele

• There is no subtitle

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Current Hemisphere of Breit Frame
DIS Event

• e-p Breit frame
• photon is space like
• ?Quarks hadronization products in current
  hemisphere

Lab Frame
Breit Frame
PT
PL
Breit Frame
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Study Jets in Breit Frame

• The Brick Wall Frame
• In leading order struck quark turns around
• ? Single jet event jet has no ET
• Dijet event jets balanced in ET
• Breit Frame helps with multijet identification

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Sphericity

• Describes isotropy of energy flow
• Measure of the summed p2T wrt. Sphericity axis

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Thrust in DIS

• Linear collimation of hadronic system along a
  specified (thrust) axis
• T interpretation depends on choice of axis

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Energy Flow and Dijets

• Instead of inclusive events, we use dijets in the
  current region of the Breit frame.
• Dijets
• pQCD part of ltFgt calculation well understood
• Event topology well understood
• New Event Shape Variables Kout, Azimuthal
  Correlation
• Must define an event plane in the Breit frame
• Use Thrust to define the event plane
• Transverse Energy Flow

axis
TT axis
TZ axis
TM axis
Tm axis
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Thrust and Sphericity
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Approach to Non-Perturbative Calculations

• pQCD prediction ? measured distribution
• Correction factors for non-perturbative (soft)
  QCD effects
• Recent theory reduces corrections for any
  infrared safe event shape variable, F
• Power Correction
• independent of any fragmentation assumptions
• non-perturbative parameter
  (Dokshitzer, Webber, Phys. Lett. B 352(1995)451)

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Kinematic Bins

• Analysis conducted in 8 bins of Q2
• Lowest two Q2 bins are divided into two bins of x
• Two studies
• Means of each variable in each bin
• Differential distributions of each variable in
  each bin