1 / 14

Single-Arm Compton Analysis

Single-Arm Compton Analysis. M. H. Wood University of Massachusetts, Amherst. Motivation. As a systemic check on the p 0 analysis, we want to analyze another reaction from the same production runs. Since the PS magnet was on, the complete 2-arm

fay-glass
Download Presentation

Single-Arm Compton Analysis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Single-Arm Compton Analysis M. H. Wood University of Massachusetts, Amherst

  2. Motivation As a systemic check on the p0 analysis, we want to analyze another reaction from the same production runs. Since the PS magnet was on, the complete 2-arm Compton scattering is not possible. An alternative is to measure the Compton scattering cross section from the scattered photon only (single-arm case). With this goal in mind, I have analyzed the energy and polar angle information of a single photon during some p0 production runs. The Compton scattering kinematics were analyzed given the scattered photon’s energy and angle measured by HyCal. This method was also tested for a few dedicated Compton scattering runs. In that case, the photon was selected from the two possible clusters.

  3. Event Selection • Number of clusters in HyCal >= 1 • At least 1 tagger photon from TRIGPHOTON bank with bit=2 • Cluster energy >= 0.5 GeV • Beamline cut : • Angular cut : 0.5o<q<1.3o • Veto cut : HYCALCLUSTER.veto < 0 • Background reduction : • Timing cut : Dt < +/- 3.5s on the timing coincidence (approximately +/- 5 ns)

  4. In time Sidebands Subtracted Energy Ratio The physical quantity used in this analysis is the energy ratio where Emeas is the measured cluster energy and ECompton is the calculated energy of the scattered photon given q and Eg.

  5. Number of Clusters In order not to bias the data sample, all clusters in an event were used to calculate the energy ratio. I also looped over all possible tagger photons in the analysis.

  6. Angular Range 0.5<q<0.7 0.5<q<0.8 0.5<q<0.9 0.5<q<0.6 0.5<q<1.3 0.5<q<1.2 0.5<q<1.0 0.5<q<1.1 In time events Sidebands 0.5<q<1.4 0.5<q<1.5

  7. Comparison with Dedicated Compton Run All clusters 1 cluster2 clusters3 clusters Run 5003 – p0 production Run 5150 – Compton

  8. Veto Study Run 5003 – p0 production Yveto/YTotal=98% Run 5150 – Compton Yveto/YTotal=46% w/o veto cut w/ veto cut w/o veto cut w/ veto cut

  9. Differential Cross Sections Compton p0 production

  10. Trigger Threshold Inefficiency Run 5003 – p0 production Trigger threshold = -88mV Run 5150 – Compton Trigger threshold = -44mV

  11. Trigger Inefficiency (cont’d) To study the trigger inefficiency, I calculated the normalized yields with various upper limit on the angular range.

  12. New Differential Cross Sections Compton p0 production 0.5o < q < 0.9o

  13. Conclusions • A single-arm compton analysis was attempted to extracted an absolute cross section. • The analysis was performed on p0 production runs as well as dedicated Compton runs. • Due to a trigger inefficiency for Compton scattering during p0 runs, an absolute cross section cannot be extracted at this time. • The analysis will continue using the relative cross section for run-to-run checks.

  14. Normalized Yield Normalized Yield Normalized Yield per Run The data are from p0 production runs with the 12C target. 0.5o <q < 0.9o 0.5o < q < 1.1o

More Related