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The biological effect of ionizing radiation is mediated practically always by the clusters of radicals formed by densely ionizing track ends of primary or secondary particles. In the case of low-LET radiation the direct effect may be practically neglected and the radical clusters meet a DNA molecule always some time after their formation. The corresponding damage effect (formation of DSB) depends then on the evolution running in individual clusters, being influenced by present chemical agents. Two main parallel processes influence then final effect: diffusion of corresponding radical clusters (lowering radical concentrations) and chemical reactions of all chemical substances present in the clusters. The processes running in the corresponding radical clusters will be modeled with the help of continuous Petri net, which enables us to study the concurrent influence of both the processes: lowering concentration of radicals due diffusion and due chemical reactions. The given model may be helpful especially when the effect of radicals on DSB formation (DNA damage) at the presence of different substances influencing radiobiological effect is to be studied.

A search for nonresonant Higgs boson pair production in the b (b) over bar gamma gamma final state is performed using 140 fb(-1) of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. This analysis supersedes and expands upon the previous nonresonant ATLAS results in this final state based on the same data sample. The analysis strategy is optimised to probe anomalous values not only of the Higgs (H) boson self-coupling modifier kappa(lambda) but also of the quartic HHVV (V = W, Z) coupling modifier kappa(2V). No significant excess above the expected background from Standard Model processes is observed. An observed upper limit mu(HH) < 4.0 is set at 95% confidence level on the Higgs boson pair production cross-section normalised to its Standard Model prediction. The 95% confidence intervals for the coupling modifiers are -1.4 < kappa(lambda) < 6.9 and -0.5 < kappa(2V) < 2.7, assuming all other Higgs boson couplings except the one under study are fixed to the Standard Model predictions. The results are interpreted in the Standard Model effective field theory and Higgs effective field theory frameworks in terms of constraints on the couplings of anomalous Higgs boson (self-)interactions.

Precise knowledge of the beam optics at the LHC is crucial to fulfill the physics goals of the TOTEM experiment, where the kinematics of the scattered protons is reconstructed with near-beam telescopes-so-called Roman pots (RP). Before being detected, the protons' trajectories are influenced by the magnetic fields of the accelerator lattice. Thus precise understanding of the proton transport is of key importance for the experiment. A novel method of optics evaluation is proposed which exploits kinematical distributions of elastically scattered protons observed in the RPs. Theoretical predictions, as well as Monte Carlo studies, show that the residual uncertainty of the optics estimation method is smaller than .

This volume of the IOP Conference Series is dedicated to scientific contributions presented at the 16th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2014), this year the motto was bridging disciplines . The conference took place on September 1-5, 2014, at the Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic. The 16th edition of ACAT explored the boundaries of computing system architectures, data analysis algorithmics, automatic calculations, and theoretical calculation technologies. It provided a forum for confronting and exchanging ideas among these fields, where new approaches in computing technologies for scientific research were explored and promoted. This year's edition of the workshop brought together over 140 participants from all over the world. The workshop's 16 invited speakers presented key topics on advanced computing and analysis techniques in physics. During the workshop, 60 talks and 40 posters were presented in three tracks: Computing Technology for Physics Research, Data Analysis - Algorithms and Tools, and Computations in Theoretical Physics: Techniques and Methods. The round table enabled discussions on expanding software, knowledge sharing and scientific collaboration in the respective areas. ACAT 2014 was generously sponsored by Western Digital, Brookhaven National Laboratory, Hewlett Packard, DataDirect Networks, M Computers, Bright Computing, Huawei and PDV-Systemhaus. Special appreciations go to the track liaisons Lorenzo Moneta, Axel Naumann and Grigory Rubtsov for their work on the scientific program and the publication preparation. ACAT's IACC would also like to express its gratitude to all referees for their work on making sure the contributions are published in the proceedings. Our thanks extend to the conference liaisons Andrei Kataev and Jerome Lauret who worked with the local contacts and made this conference possible as well as to the program coordinator Federico Carminati and the conference chair Denis Perret-Gallix for their global supervision. Further information on ACAT 2014 can be found at http://www.particle.cz/acat2014

Quality monitoring is a crucial part in struggle for reliability of every Tier 2 site. We present a solution based on Nagios installation in Prague. Our solution includes both third party and in-house developed add-ons and plug-ins. We focus on integrating results from grid-wise monitoring tools (such as SAM or Gstat) at one place (our Nagios instance). We also present an automated way to generate configuration files for Nagios from local database of hardware and services.

The TOTEM experiment at the CERN LHC has measured elastic proton–proton scattering at the centre-of-mass energy s = 8 TeV and four-momentum transfers squared, | t |, from 6 × 10 - 4 to 0.2 GeV 2 . Near the lower end of the t -interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second- or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the ρ -parameter is found to be 0.12 ± 0.03 . The results for the total hadronic cross-section are σ tot = ( 102.9 ± 2.3 )  mb and ( 103.0 ± 2.3 )  mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.

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 0.2GeV2<|t|<1.9GeV2. 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=8TeV yields the positions, |t|dip=(0.521±0.007)GeV2 and |t|bump=(0.695±0.026)GeV2, as well as the cross-section values, dσ/dtdip=(15.1±2.5)μb/GeV2 and dσ/dtbump=(29.7±1.8)μb/GeV2, for the dip and the bump, respectively.

The proton–proton elastic differential cross section$${\\mathrm{d}}\\sigma /{\\mathrm{d}}t$$d σ / d t has been measured by the TOTEM experiment at$$\\sqrt{s}=2.76\\hbox { TeV}$$s = 2.76 TeV energy with$$\\beta ^{*}=11\\hbox { m}$$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 to$$0.74\\hbox { GeV}^{2}$$0.74 GeV 2 . The differential cross-section can be described with an exponential in the | t |-range between 0.36 and$$0.54\\hbox { GeV}^{2}$$0.54 GeV 2 , followed by a diffractive minimum (dip) at$$|t_{\\mathrm{dip}}|=(0.61\\pm 0.03)\\hbox { GeV}^{2}$$| t dip | = ( 0.61 ± 0.03 ) GeV 2 and a subsequent maximum (bump). The ratio of the$${\\mathrm{d}}\\sigma /{\\mathrm{d}}t$$d σ / d t at the bump and at the dip is$$1.7\\pm 0.2$$1.7 ± 0.2 . When compared to the proton–antiproton measurement of the D0 experiment at$$\\sqrt{s} = 1.96\\hbox { TeV}$$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 the exchange of a colourless C-odd three-gluon compound state in the t -channel of the proton–proton and proton–antiproton elastic scattering.

The proton–proton elastic differential cross section d σ / d t 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 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 d σ / d t 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 the exchange of a colourless C-odd three-gluon compound state in the t -channel of the proton–proton and proton–antiproton elastic scattering.

The TOTEM collaboration has measured the elastic proton-proton differential cross section \\[\\mathrm{d}\\sigma /\\mathrm{d}t\\] at \\[\\sqrt{s}=13\\] TeV LHC energy using dedicated \\[\\beta ^{*}=90\\] m beam optics. The Roman Pot detectors were inserted to 10\\[\\sigma \\] distance from the LHC beam, which allowed the measurement of the range [0.04 GeV\\[^{2}\\]; 4 GeV\\[^{2}\\]\\[]\\] in four-momentum transfer squared |t|. The efficient data acquisition allowed to collect about 10\\[^{9}\\] elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-|t| tail. The average nuclear slope has been found to be \\[B=(20.40 \\pm 0.002^{\\mathrm{stat}} \\pm 0.01^{\\mathrm{syst}})~\\]GeV\\[^{-2}\\] in the |t|-range 0.04–0.2 GeV\\[^{2}\\]. The dip position is \\[|t_{\\mathrm{dip}}|=(0.47 \\pm 0.004^{\\mathrm{stat}} \\pm 0.01^{\\mathrm{syst}})~\\]GeV\\[^{2}\\]. The differential cross section ratio at the bump vs. at the dip \\[R=1.77\\pm 0.01^{\\mathrm{stat}}\\] has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.