"Adopted" Wisconsin Student I was a PhD student with Klaus - - PowerPoint PPT Presentation

Nils Krumnack (Iowa State University)

"Adopted" Wisconsin Student

• I was a PhD student with Klaus Wick at the University of Hamburg
• build a small detector component for my masters
• continued on to do a physics analysis for my PhD
• my advisor at Hamburg didn’t "do" physics analysis
• encouraged me to look elsewhere for support
• Wisconsin group was a good fit for me
• my advisor knew Wesley for his hardware expertise
• assumed he would be just as good at analysis
• became a Wisconsin student in many ways
• moved into the Wisconsin office, joined the group meetings…
• regular discussions with all Wisconsin students
• Wesley was one of two members of my defense committee

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Nils Krumnack (Iowa State University)

Physics Analysis

• measured αS in trijet to dijet cross section ratio in DIS
• ratio of αS2 to αS processes
• used "new" NLO calculations for αS2 processes
• exact same analysis as Liang Li
• ZEUS had policy of two


independent analysises

• meant as cross check


against mistakes

• many afternoons/evenings

• f analysis comparisons
• cut flows, event dumps, …
• graduated year ahead of Liang
• he finished up the publication

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ZEUS

10

• 3

10

• 2

10

• 1

1 10

dσ / dQ2 (pb/GeV2)

ZEUS (prel.) 98-00 Dijets ZEUS (prel.) 98-00 Trijets Mn-jet > 25 GeV NLO (1 + δhadr) : O(αs2) NLO (1 + δhadr) : O(αs3) Energy Scale Uncertainty a) 0.75 1 1.25 1.5 Dijets / NLO : O(αs2) NLO : 1/16 < µr

2 / (Q2+E – T 2) < 1

b)

data / theory

0.6 0.8 1 1.2 1.4 1.6 10

2

10

3

data / theory Q2 (GeV2)

Trijets / NLO : O(αs3) NLO : 1/16 < µr

2 / (Q2+E – T 2) < 1

c)

Nils Krumnack (Iowa State University)

Hardware Work

• did hardware project before joining Wisconsin group
• small calorimeter inside accelerator magnet
• part of the luminosity system
• tagging electrons from ep->epγ
• had a little cooling accident during my PhD
• turns out machinable tungsten


can rust…

• needed complete rebuilding
• Wisconsin students got involved in


rebuilding the detector:

• helped in reassembling the detector
• participated in test beam measurements

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