Engineering topics

Ivanchenko, V.

Publications and source records attributed to Ivanchenko, V..

4 records

DOE OSTI2022

Characterisation of the dip-bump structure observed in proton–proton elastic scattering at $\sqrt{s}$ = 8 TeV

The TOTEM collaboration at the CERN LHC has measured the differential cross-section of elastic proton–proton scattering at √s = 8TeV in the squared four-momentum transfer range 0.2GeV 2 < |t| < 1.9GeV 2 . This interval includes the structure with a diffractive minimum (“dip”) and a secondary maximum (“bump”) that has also been observed at all other LHC energies, where measurements were made. A detailed characterisation of this structure for √s = 8 TeV yields the positions, |t| dip = (0.521 ± 0.007)GeV 2 and |t| bump = (0.695 ± 0.026)GeV 2 , as well as the cross-section values, dσ/dt| dip = (15.1 ± 2.5)μb/GeV 2 and dσ/dt| bump = (29.7 ± 1.8)μb/GeV 2 , for the dip and the bump, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Report on G4-Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Simulation Benchmarking Group

Geant4 is a Monte Carlo code extensively used in medical physics for a wide range of applications, such as dosimetry, micro- and nanodosimetry, imaging, radiation protection, and nuclear medicine. Geant4 is continuously evolving, so it is crucial to have a system that benchmarks this Monte Carlo code for medical physics against reference data and to perform regression testing. In this work, to respond to these needs, we developed G4-Med, a benchmarking and regression testing system of Geant4 for medical physics. G4-Med currently includes 18 tests. They range from the benchmarking of fundamental physics quantities to the testing of Monte Carlo simulation setups typical of medical physics applications. Both electromagnetic and hadronic physics processes and models within the prebuilt Geant4 physics lists are tested. The tests included in G4-Med are executed on the CERN computing infrastructure via the use of the geant-val web application, developed at CERN for Geant4 testing. The physical observables can be compared to reference data for benchmarking and to results of previous Geant4 versions for regression testing purposes. This paper describes the tests included in G4-Med and shows the results derived from the benchmarking of Geant4 10.5 against reference data.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2020

Elastic differential cross-section ${\mathrm{d}}\sigma /{\mathrm{d}}t$ at $\sqrt{s}=2.76\hbox {TeV}$ and implications on the existence of a colourless C-odd three-gluon compound state

The proton-proton elastic differential cross section dσ/dt has been measured by the TOTEM experiment at √ s = 2.76 TeV energy with β* = 11 m beam optics. The Roman Pots were inserted to 13 times the transverse beam size from the beam, which allowed to measure the differential cross-section of elastic scattering in a range of the squared four-momentum transfer (|t|) from 0.36 GeV 2 to 0.74 GeV 2 . The differential cross-section can be described with an exponential in the |t|-range between 0.36 and 0.54 GeV 2 , followed by a diffractive minimum (dip) at |t dip | = (0.61 ± 0.03) GeV 2 and a subsequent maximum (bump). The ratio of the dσ/dt at the bump and at the dip is 1.7±0.2. When compared to the proton–antiproton measurement of the D0 experiment at √ s = 1.96 TeV, a significant difference can be observed. Under the condition that the effects due to the energy difference between TOTEM and D0 can be neglected, the result provides evidence for a colourless C-odd three-gluon bound state exchange in the t-channel of the proton-proton and proton–antiproton elastic scattering.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

GEANT4 parameter tuning using Professor

The GEANT4 toolkit is used extensively in high energy physics to simulate the passage of particles through matter and to predict effects such as detector efficiencies and smearing. GEANT4 uses many underlying models to predict particle interaction kinematics, and uncertainty in these models leads to uncertainty in high energy physics measurements. The GEANT4 collaboration recently made free parameters in some models accessible through partnership with GEANT4 developers. We present a study of the impact of varying parameters in three GEANT4 hadronic physics models on agreement with thin target datasets and describe fits to these datasets using the Professor model tuning framework [1]. We find that varying parameters produces substantially better agreement with some datasets, but that more degrees of freedom are required for full agreement. This work is a first step towards a common framework for propagating uncertainties in GEANT4 models to high energy physics measurements, and we outline future work required to complete that goal.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗