Phi Analysis

1
Phi Analysis

• Jonathan Adkins
• Wednesday July 27th
• ? d ? p ? (n)
• ? p ? p ?

2
General Overview

• Brief overview of experiment
• Efficiency calculations
• General calculations for ? d ? p ? (n)

3
Thomas Jefferson National Accelerator Facility
(JLab)

• CEBAF (Continuous Electron Beam Accelerator)
• Bremsstrahlung photon tagger

4
G10 Experiment at J-Lab

• CLAS (CEBAF Large Acceptance Spectrometer)
  Collaboration
• CEBAF Continous Electron Beam Accelerator
  Facility
• Liquid hydrogen and liquid deuterium targets

5
Reactions

• ? d ? p ? (n)
• ? d ? p K K- (n)
• Possible to have sub-threshold reaction
• ? p ? p ?
• ? p ? p K K-
• No sub-threshold reaction

• ? particle decays quickly
• ? 20 x 10-23 sec
• Particles detected
• p K K-
• Neutron not detected, because no charge.

6
Goals

• Investigate the properties of ? in the deuterium
  sub-threshold reaction.
• Eventually, replace the deuterium target with a
  heavier target (eg. C-12) in order to investigate
  the interaction of ? with protons and neutrons.

• This is of interest because of the possibility of
  a bound state between the ? and the neutron.
• Neutron
• ? - ss
• All currently known bound states are between 3
  quark particles.

7
Efficiency hydrogen target

• Calculation
• Effic (K) Effic(p K K-) / Effic(p X K-)
• Total events (p K K-) / Total events (p X K-)

• METHOD EXAMPLE K efficiency
• Particles detected
• p K K-
• Total efficiency Effic (p) Effic (K)
  Effic(K-)
• Particles detected
• p X K-
• Total efficiency Effic (p) Effic(K-)

8
Cuts

• The following cuts must be made
• Proton acceptance
• K acceptance
• K- acceptance
• Missing mass

9
Low field K acceptance cuts
Proton acceptance
K- acceptance
10
Low field K acceptance cuts
Proton acceptance
K- acceptance
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Low field K missing mass cuts
Missing mass
12
Low field K missing mass cuts
Missing mass
13
Low field K theta distribution
After cuts
Before cuts
14
Low field K comparison
pXK-
pKK-
15
Low field K efficiency
16
Low field K- efficiency
17
Low field P efficiency
18
Field settings

• Two magnetic field settings because of the
  previous set up for pentaquark research.
• Low 2550 Torus
• High 3375 Torus
• For our experiment there should be no difference

19
Low field K efficiency
20
High field K efficiency
21
Low field K efficiency
22
High field K efficiency
23
Low field K- efficiency
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High field K- efficiency
25
Low field K- efficiency
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High field K- efficiency
27
Low field K- missing mass cuts
Missing mass
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Low field K missing mass cuts
Missing mass
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Low field P efficiency
30
High field P efficiency
31
Low field P efficiency
32
High field P efficiency
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pX

• Try only detecting p
• Cuts on proton acceptance, and on missing mass of
  KK-
• See if any sense can be made of this?

34
KK- missing mass
35
KK- missing mass
36
KK- efficiency
37
Results of pX

• Ideally, compare
• Effic(K) Effic(K-) with Effic(KK-)
• No results that merit comparison, need to find
  another way to calculate Effic(KK-)

38
General calculations for ? d ? p ? (n)

• Attempt to compare high and low field for
  similarities
• Make cuts that will remove alternate production
  methods of K and K- particles.
• Compare below threshold data to above threshold
  data