skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Production Mechanism Lifetimes of Charmed Particles

Abstract

The discovery of the $$J/\psi$$; in 1974 [1], a resonance consisting of a charmed quarkantiquark pair was a major turning point in elementary particle physics. Predicted ten years earlier [2] to help explain the absence of strangeness changing neutral currents, the charm quark was expected to decay weakly into a strange quark [3]. The charm quark was also very important in the GW (Glashow, Iliopoulos and Maiani) model [4] of weak interactions. The $$J/\psi$$; provided indirect evidence for the existence of charm. However, it was not until two years later with the discovery [5] of the D0 that a particle with net charm was observed. A number of experiments subsequently looked for and discovered other charmed particles [6], 7J. The main difficulties in studying charmed particles are their short lifetimes ($$\tau \approx 10^{-13}$$ sec.) and low production rates ($$\sigma(pp \to c\bar{c} + X) \approx$$ = 80 $$\pm 60,\mu b$$) [7]. The short lifetimes correspond to very short decay lengths, of the order of a few hundred microns for charmed particles with a few GeV/c momentum. Due to the short decay length, nuclear emulsion with its high spatial resolution is an ideal detector since it is possible to actually see themore » production and subsequent decay of the charm particle. In 1977 a hybrid emulsion-spectrometer experiment (E-531) was set up in the wide-band neutrino beam at Fermilab. An advantage of the neutrinos is that they do not produce any tracks in the emulsion; therefore the background is very low and it is possible to leave the emulsion target in the beam for several months. Results using data collected from November 1978 to February 1979 (referred to as the first run) have already been published in 'numerous theses [8,9,10,11] and articles [12,13,14,15,16,17]. The exposure time was only about four months while the search for events in the emulsion and their subsequent analysis took several years. This thesis will discuss the data obtained in a second run of the experiment which collected data from November 1980 to May 1981, and will combine the data of the two runs together. This experiment was one of the first to obtain a large enough number of charmed particles to measure the lifetimes accurately. It was also the first experiment able to study the production of charmed particles by neutrinos .« less

Authors:
 [1]
  1. Ottawa U.
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1433229
Report Number(s):
FERMILAB-THESIS-1987-22
259376
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Frederiksen, Soren Grandborg. The Production Mechanism Lifetimes of Charmed Particles. United States: N. p., 1987. Web. doi:10.2172/1433229.
Frederiksen, Soren Grandborg. The Production Mechanism Lifetimes of Charmed Particles. United States. https://doi.org/10.2172/1433229
Frederiksen, Soren Grandborg. Thu . "The Production Mechanism Lifetimes of Charmed Particles". United States. https://doi.org/10.2172/1433229. https://www.osti.gov/servlets/purl/1433229.
@article{osti_1433229,
title = {The Production Mechanism Lifetimes of Charmed Particles},
author = {Frederiksen, Soren Grandborg},
abstractNote = {The discovery of the $J/\psi$; in 1974 [1], a resonance consisting of a charmed quarkantiquark pair was a major turning point in elementary particle physics. Predicted ten years earlier [2] to help explain the absence of strangeness changing neutral currents, the charm quark was expected to decay weakly into a strange quark [3]. The charm quark was also very important in the GW (Glashow, Iliopoulos and Maiani) model [4] of weak interactions. The $J/\psi$; provided indirect evidence for the existence of charm. However, it was not until two years later with the discovery [5] of the D0 that a particle with net charm was observed. A number of experiments subsequently looked for and discovered other charmed particles [6], 7J. The main difficulties in studying charmed particles are their short lifetimes ($\tau \approx 10^{-13}$ sec.) and low production rates ($\sigma(pp \to c\bar{c} + X) \approx$ = 80 $\pm 60,\mu b$) [7]. The short lifetimes correspond to very short decay lengths, of the order of a few hundred microns for charmed particles with a few GeV/c momentum. Due to the short decay length, nuclear emulsion with its high spatial resolution is an ideal detector since it is possible to actually see the production and subsequent decay of the charm particle. In 1977 a hybrid emulsion-spectrometer experiment (E-531) was set up in the wide-band neutrino beam at Fermilab. An advantage of the neutrinos is that they do not produce any tracks in the emulsion; therefore the background is very low and it is possible to leave the emulsion target in the beam for several months. Results using data collected from November 1978 to February 1979 (referred to as the first run) have already been published in 'numerous theses [8,9,10,11] and articles [12,13,14,15,16,17]. The exposure time was only about four months while the search for events in the emulsion and their subsequent analysis took several years. This thesis will discuss the data obtained in a second run of the experiment which collected data from November 1980 to May 1981, and will combine the data of the two runs together. This experiment was one of the first to obtain a large enough number of charmed particles to measure the lifetimes accurately. It was also the first experiment able to study the production of charmed particles by neutrinos .},
doi = {10.2172/1433229},
url = {https://www.osti.gov/biblio/1433229}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1987},
month = {1}
}

Thesis/Dissertation:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this thesis or dissertation.

Save / Share: