The strong electromagnetic fields associated with ultra-relativistic protons and nuclei correspond to an equivalent flux of photons. At the future Large Hadron Collider at CERN, the corresponding ...photon-nucleon center of mass energies will be higher than at any existing accelerator. The experimental and theoretical aspects of particle production in electromagnetic interactions at hadron colliders are reviewed.
The Lifestyle-integrated Functional Exercise (LiFE) program is an effective but resource-intensive fall prevention program delivered one-to-one in participants' homes. A recently developed ...group-based LiFE (gLiFE) could enhance large-scale implementability and decrease resource intensity. The aim of this qualitative focus group study is to compare participants' experiences regarding acceptability of gLiFE vs LiFE.
Programs were delivered in seven group sessions (gLiFE) or seven individual home visits (LiFE) within a multi-center, randomized non-inferiority trial. Four structured focus group discussions (90-100 min duration; one per format and study site) on content, structure, and subjective effects of gLiFE and LiFE were conducted. Qualitative content analysis using the method of inductive category formation by Mayring was applied for data analysis. Coding was managed using NVivo.
In both formats, participants (N = 30, 22 women, n
= 15, n
= 15, mean age 78.8 ± 6.6 years) were positive about content, structure, and support received by trainers. Participants reflected on advantages of both formats: the social aspects of learning the program in a peer group (gLiFE), and benefits of learning the program at home (LiFE). In gLiFE, some difficulties with the implementation of activities were reported. In both formats, the majority of participants reported positive outcomes and successful implementation of new movement habits.
This is the first study to examine participants' views on and experiences with gLiFE and LiFE, revealing strengths and limitations of both formats that can be used for program refinement. Both formats were highly acceptable to participants, suggesting that gLiFE may have similar potential to be adopted by adults aged 70 years and older compared to LiFE.
ClinicalTrials.gov , NCT03462654 . Registered on March 12, 2018.
We discuss the physics of large impact parameter interactions at the LHC: ultraperipheral collisions (UPCs). The dominant processes in UPCs are photon–nucleon (nucleus) interactions. The current LHC ...detector configurations can explore hard phenomena at small
x
with nuclei and nucleons at photon–nucleon center-of-mass energies above 1 TeV, extending the
x
range of HERA by a factor of ten. In particular, it will be possible to probe diffractive and inclusive parton densities in nuclei using several processes. The interaction of small dipoles with protons and nuclei can be investigated in elastic and quasi-elastic
J
/
ψ
and
Υ
production as well as in high
t
ρ
0
production accompanied by a rapidity gap. Several of these phenomena provide clean signatures of the onset of the new high gluon density QCD regime. The LHC is in the kinematic range where nonlinear effects are several times larger than those at HERA. Two-photon processes in UPCs are also studied. In addition, while UPCs play a role in limiting the maximum beam luminosity, they can also be used as a luminosity monitor by measuring mutual electromagnetic dissociation of the beam nuclei. We also review similar studies at HERA and RHIC as well as describe the potential use of the LHC detectors for UPC measurements.
The STAR Time Projection Chamber (TPC) is used to record the collisions at the Relativistic Heavy Ion Collider. The TPC is the central element in a suite of detectors that surrounds the interaction ...vertex. The TPC provides complete coverage around the beam-line, and provides complete tracking for charged particles within ±1.8 units of pseudo-rapidity of the center-of-mass frame. Charged particles with momenta greater than
100
MeV/c
are recorded. Multiplicities in excess of 3000 tracks per event are routinely reconstructed in the software. The TPC measures
4
m
in diameter by
4.2
m
long, making it the largest TPC in the world.
This study explores the relationship between corruption and conflict in northern Uganda, using the perspectives of local business owners as an inroad. The purpose is to highlight how various types of ...corruption can be related to conflict dynamics in different ways, depending on the context. The article argues that in post-war northern Uganda grand corruption can be seen as related to the conflict dynamics, while petty corruption is generally not seen that way. At the centre of the conflict in northern Uganda lies a deep mutual mistrust between the population in the north and the central government. Therefore corruption in the public sector that occurs at the central level, in particular with regard to funds aimed at the north, tends to be associated with the conflict, whereas the various types of petty corruption encountered by local businesspersons in Gulu, the largest town in northern Uganda, are seen by these actors as normal or as 'the way things are'.
PHYSICS OF ULTRA-PERIPHERAL NUCLEAR COLLISIONS Bertulani, Carlos A.; Klein, Spencer R.; Nystrand, Joakim
Annual review of nuclear and particle science,
12/2005, Letnik:
55, Številka:
1
Journal Article
Recenzirano
Odprti dostop
▪ Abstract Moving highly-charged ions carry strong electromagnetic fields that act as a beam of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ...ions interact through photon-ion and photon-photon collisions known as ultra-peripheral collisions (UPCs). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron, and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond that accessible elsewhere; the LHC will reach a γp energy ten times that of the Hadron-Electron Ring Accelerator (HERA). Reactions as diverse as the production of anti-hydrogen, photoproduction of the ρ
0
, transmutation of lead into bismuth, and excitation of collective nuclear resonances have already been studied. At the LHC, UPCs can study many types of new physics processes.
This report reviews the study of open heavy-flavour and quarkonium production in high-energy hadronic collisions, as tools to investigate fundamental aspects of Quantum Chromodynamics, from the ...proton and nucleus structure at high energy to deconfinement and the properties of the Quark–Gluon Plasma. Emphasis is given to the lessons learnt from LHC Run 1 results, which are reviewed in a global picture with the results from SPS and RHIC at lower energies, as well as to the questions to be addressed in the future. The report covers heavy flavour and quarkonium production in proton–proton, proton–nucleus and nucleus–nucleus collisions. This includes discussion of the effects of hot and cold strongly interacting matter, quarkonium photoproduction in nucleus–nucleus collisions and perspectives on the study of heavy flavour and quarkonium with upgrades of existing experiments and new experiments. The report results from the activity of the SaporeGravis network of the I3 Hadron Physics programme of the European Union 7
th
Framework Programme.
We discuss the photoproduction of Upsilon and J/psi at high energy pp, pp, and heavy ion colliders. We predict large rates in pp interactions at the Fermilab Tevatron and in pp and heavy ion ...interactions at the CERN Large Hadron Collider. The J/psi is also produced copiously at the Relativistic Heavy Ion Collider. These reactions can be used to study the gluon distribution in protons and heavy nuclei. We also show that the different CP symmetries of the initial states lead to large differences in the transverse momentum spectra of mesons produced in pp vs pp collisions.
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