Search for Excited Cascade Hyperons (Ξ*-) using the CLAS12 Spectrometer at Jefferson Laboratory

Authors

Achyut Khanal, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Physics

First Advisor's Name

Brian A. Raue

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Lei Guo

Second Advisor's Committee Title

Co-Committee Chair

Third Advisor's Name

Daniel S. Carman

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Misak M. Sargsian

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

David Chatfield

Fifth Advisor's Committee Title

Committee member

Keywords

CLAS12, Forward Detector, Central Detector, Forward Tagger, CLAS12 Upgrade, RG-A, RGA, Fall 2018, Inbending, Outbending, Spring 2019, E12−11−005A, E12−11−005, CASH, Statistics, GammaPy, Baryon Spectroscopy, Cascade Hyperons, Upper Limit Cross Section, Cross Section, Upper Limit, Differential Cross Section, Efficiency, Acceptance, Momentum Smearing, Chi2 Minimization, Fit Statistics, Cash Counts, Event Mixing Technique, Missing Mass Technique, Missing Mass, MM, eK+K+K+(Y), MM(e'K+K+), MM(e'K+K+K-), Background modeling, BG, Test Statistics, TS, maximum log-likelihood ratio test, Likelihood Ratio, Hypothesis Testing, Null Hypothesis, Alternative Hypothesis, Excess and Significance, Signal Strength, Physics, Weak, Nuclear, Polarization, Particle, Baryon, Meson, Strange, Quark, Kaon, Photoproduction, Electroproduction, Jlab, Jefferson, Lab, Photon, Lambda, Production, Gamma, K+, P, K-, FIU, Achyut, Khanal, Experimental, Accelerator, g12, CLAS, Achyut Khanal, Nuclear Physics, Particle Physics, Hyperon, Weak Decay, Strong Decay, Jlab, Jefferson Lab, Thomas Jefferson National Accelerator Facility, Very Strange Physics, Double Strangeness, Production Mechanism

Date of Defense

10-11-2022

Abstract

The number of experimentally observed doubly strange Cascade states to date is far fewer than has been predicted theoretically. The CLAS12 Very Strange physics program (E12 − 11 − 005A) at the Thomas Jefferson National Accelerator Facility aims to study the electroproduction of these states using the newly upgraded CEBAF Large Acceptance Spectrometer for 12 GeV (CLAS12) in experimental Hall B. In this project, the reaction ep → e′K⁺K⁺Ξ^*-→ e′K⁺K⁺K^-(Λ/Σ⁰) is studied using CLAS12 Run Group A (RG-A) data sets taken by impinging electron beams of 10.2 and 10.6 GeV energies on an LH2 target. Scattered electrons are detected with either the Forward Detector (FD), covering a polar angle range of 5^o to 35^o to study electroproduction, or with the Forward Tagger (FT), covering a polar angle range of 2.5^o to 4.5^o, to study quasi-real photoproduction. The CLAS12 detector with nearly a 4π solid angle coverage is used to detect scattered electrons and charged kaons in the final state. Λ/Σ⁰ hyperons are reconstructed using the missing mass technique to explore intermediate doubly-strange hyperons (Ξ^*-) that decay to K^- and Λ/Σ⁰. No statistically significant Ξ^*- states other than the Ξ^*-(1530) were found in the missing mass spectra based on the currently available statistics in the CLAS12-FD acceptance only. A maximum log-likelihood method is implemented to determine the statistical significance and the upper limits on the Ξ^*-(1820) electroproduction cross section by constructing 95% confidence level boundaries on the Ξ^*-(1820) yields. Additional research was conducted to investigate the upper limit electroproduction cross section of the reaction ep → e′K⁺K⁺Ξ^*-→ e′K⁺K⁺K^-(Λ/Σ⁰) as a function of the electroproduced Ξ^*- mass and the differential cross section ( dσ/dMM(e′K⁺K⁺)) as a function of missing mass MM(e′K⁺K⁺) for electroproduction and quasi-real photoproduction processes.

Identifier

FIDC010852

ORCID

0000-0002-0749-9444

Recommended Citation

Khanal, Achyut, "Search for Excited Cascade Hyperons (Ξ*-) using the CLAS12 Spectrometer at Jefferson Laboratory" (2022). FIU Electronic Theses and Dissertations. 5227.
https://digitalcommons.fiu.edu/etd/5227