eprintid: 36824
rev_number: 15
eprint_status: archive
userid: 9125
dir: disk0/00/03/68/24
datestamp: 2025-07-11 08:53:17
lastmod: 2025-07-15 11:43:49
status_changed: 2025-07-11 08:53:17
type: doctoralThesis
metadata_visibility: show
creators_name: van Veen, Casper Arie
title: Simulation Studies for Measuring the Soft-Photon Spectrum with the ALICE 3 Forward Conversion Tracker
subjects: ddc-500
subjects: ddc-530
divisions: i-130200
adv_faculty: af-13
keywords: ALICE 3, Low's theorem, soft-photon puzzle, Forward Conversion Tracker, FCT
cterms_swd: ALICE
cterms_swd: CERN
cterms_swd: LHC
cterms_swd: Photon
cterms_swd: Physics
abstract: The soft-photon puzzle has been an open problem in high energy particle physics for many years
now. Experiments have been performed in the past to try to measure the soft-photon spectrum of
inelastic m → n scattering processes. Some measured an excess of a factor 4–8 in terms of the internal
bremsstrahlung spectrum predicted by Low’s theorem, but others measured no excess at all. This
work presents for the first time a full Monte Carlo simulation with generated internal bremsstrahlung
photons predicted by Low’s theorem propagated through the detector setup of ALICE 3. One of the
goals of the proposed ALICE 3 experiment is to measure the soft-photon spectrum with the use of
the Forward Conversion Tracker through the tracking of e+e− conversion pairs in a separate dipole
magnetic field. Through dedicated studies of the (spatial) origin of the various sources of background,
cuts and vetoes are implemented to minimize its impact on the measurement. These studies show
a significance of 5–10 in the regime of 0.5 < kT < 7.5 MeV/c for the case where the excess is 4
times the predicted internal bremsstrahlung spectrum. A conical modification of the beam pipe is
suggested to reduce the material budget in front of the FCT and as such the kinematic regime where
the significance exceeds 5 is extended to 0.5 < kT < 10 MeV/c for the case where the excess is 4 times
the predicted internal bremsstrahlung spectrum. In this thesis the theory, previous measurements and
the performance of the proposed Forward Conversion Tracker will be discussed.
date: 2025
id_scheme: DOI
id_number: 10.11588/heidok.00036824
ppn_swb: 1930525400
own_urn: urn:nbn:de:bsz:16-heidok-368244
date_accepted: 2025-07-04
advisor: HASH(0x5649e81c0fb0)
language: eng
bibsort: VANVEENCASIMULATION20250708
full_text_status: public
place_of_pub: Heidelberg
citation:   van Veen, Casper Arie  (2025) Simulation Studies for Measuring the Soft-Photon Spectrum with the ALICE 3 Forward Conversion Tracker.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/36824/1/Doctoral%20thesis%20Cas%20van%20Veen.pdf