Tevatron bunch length studies at CDF

Jones, Matthew ; Kephart, Bob ; Vidal, and Rick

Fermi National Accelerator Laboratory

关键词: Probability;    Protons;    Fermilab Tevatron;    43 Particle Accelerators;    Sensitivity;   

DOI  :  10.2172/794464
RP-ID  :  FERMILAB-TM-2172
RP-ID  :  AC02-76CH03000
RP-ID  :  794464

美国|英语

来源: UNT Digital Library

【 摘 要 】

A luminous interaction region can be described by the distribution in (x, y, z) over which p{bar p} interactions are observed in a detector. The spatial size of this distribution can be written in terms of expressions that involve only combinations of the proton and anti-proton bunch sizes. Hence, it is not possible to determine the sizes of the proton and anti-proton bunches independently by fitting the distribution of (x, y, z) from the recorded events. If, in addition to the coordinates (x, y, z) at which p{bar p} interactions occur, the times at which the interactions took place are also measured, then it becomes possible to measure the lengths of the proton and anti-proton bunches separately. This sensitivity is due to a correlation between z and t that arises from the fact that the proton and anti-proton bunches travel in opposite directions. The derivation presented in section 2 quantifies this correlation, resulting in an expression for the probability density as a function of z and t for p{bar p} interactions. By fitting the distributions observed at CDF using this model, we measure the lengths of the proton and anti-proton bunches at times throughout several Tevatron stores. From this analysis the evolution of the bunch lengths can be studied. We attempt to correlate these with other measures of the bunch length obtained using different experimental techniques.