M. Ruspa

We present the FP420 R&D project, which has been studying the key aspects of the development and installation of a silicon tracker and fast-timing detectors in the LHC tunnel at 420 m from the interaction points of the ATLAS and CMS experiments. These detectors would measure precisely very forward protons in conjunction with the corresponding central detectors as a means to study Standard Model (SM) physics, and to search for and characterise new physics signals. This report includes a detailed description of the physics case for the detector and, in particular, for the measurement of Central Exclusive Production, pp→p+ϕ+p, in which the outgoing protons remain intact and the central system ϕ may be a single particle such as a SM or MSSM Higgs boson. Other physics topics discussed are γγ and γp interactions, and diffractive processes. The report includes a detailed study of the trigger strategy, acceptance, reconstruction efficiencies, and expected yields for a particularpp→pHp measurement with Higgs boson decay in theb mode. The document also describes the detector acceptance as given by the LHC beam optics between the interaction points and the FP420 location, the machine backgrounds, the new proposed connection cryostat and the moving (``Hamburg'') beam-pipe at 420 m, and the radio-frequency impact of the design on the LHC. The last part of the document is devoted to a description of the 3D silicon sensors and associated tracking performances, the design of two fast-timing detectors capable of accurate vertex reconstruction for background rejection at high-luminosities, and the detector alignment and calibration strategy.

A dual-radiator Ring Imaging Cherenkov (dRICH) will provide charged hadrons particle identification in the hadronic end-cap of a general-purpose experiment at the future Electron–Ion Collider (EIC). We developed a prototype to test the performance and validate the use of Silicon Photo-Multipliers (SiPM), the baseline photo-sensor candidate for the dRICH. They provide a cheap, highly efficient technology and they are not sensitive to the high magnetic field. The general features of the detector, a detailed view of the prototype and its different configurations, the test beam performed, and the preliminary results we obtained are presented.

In order to extend the tracking acceptance, to improve the primary and secondary vertex reconstruction and thus enhancing the tagging capabilities for short lived particles, the ZEUS experiment at the HERA Collider at DESY installed a silicon strip vertex detector. The barrel part of the detector is a 63 cm long cylinder with silicon sensors arranged around an elliptical beampipe. The forward part consists of four circular shaped disks. In total just over 200k channels are read out using 2.9m2 of silicon. In this report a detailed overview of the design and construction of the detector is given and the performance of the completed system is reviewed.

In the last years, high-resolution time tagging has emerged as the tool to tackle the problem of high-track density in the detectors of the next generation of experiments at particle colliders. Time resolutions below 50ps and event average repetition rates of tens of MHz on sensor pixels having a pitch of 50$\mu$m are typical minimum requirements. This poses an important scientific and technological challenge on the development of particle sensors and processing electronics. The TIMESPOT initiative (which stands for TIME and SPace real-time Operating Tracker) aims at the development of a full prototype detection system suitable for the particle trackers of the next-to-come particle physics experiments. This paper describes the results obtained on the first batch of TIMESPOT silicon sensors, based on a novel 3D MEMS (micro electro-mechanical systems) design. Following this approach, the performance of other ongoing silicon sensor developments has been matched and overcome, while using a technology which is known to be robust against radiation degradation. A time resolution of the order of 20ps has been measured at room temperature suggesting also possible improvements after further optimisations of the front-end electronics processing stage.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Three-dimensional (3-D) silicon detectors are characterized by cylindrical electrodes perpendicular to the surface and penetrate into the bulk material in contrast to standard Si detectors with planar electrodes on the top and bottom. This geometry renders them particularly interesting to be used in environments where standard silicon detectors have limitations, such as, for example, the radiation environment expected in an upgrade to the Large Hadron Collider at CERN. For the first time, several 3-D sensors were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip and readout electronics. Devices with different electrode configurations have been characterized in a 100 GeV pion beam at the CERN SPS. Here, we report results on unirradiated devices with three 3–D electrodes per 50<formula formulatype="inline"> <tex Notation="TeX">$\,\times \,$</tex></formula>400 <formula formulatype="inline"> <tex Notation="TeX">$\mu {\rm m}^{2}$</tex></formula> pixel area. Full charge collection is obtained already with comparatively low bias voltages around 10 V. Spatial resolution with binary readout is obtained as expected from the cell dimensions. Efficiencies of 95.9%<formula formulatype="inline"><tex Notation="TeX">$ \pm$</tex></formula>0.1% for tracks incident parallel to the electrodes and of 99.9%<formula formulatype="inline"><tex Notation="TeX">$ \pm$</tex></formula>0.1% for tracks incident at 15<formula formulatype="inline"> <tex Notation="TeX">$^{\circ}$</tex></formula> are measured. The homogeneity and charge sharing of the efficiency over the pixel area are measured. </para>

Two-particle azimuthal correlations have been measured in neutral current deep inelastic ep scattering with virtuality Q2> 5 GeV2 at a centre-of-mass energy $$ \sqrt{s} $$ = 318 GeV recorded with the ZEUS detector at HERA. The correlations of charged particles have been measured in the range of laboratory pseudorapidity −1.5 < η < 2.0 and transverse momentum 0.1 < pT< 5.0 GeV and event multiplicities Nch up to six times larger than the average 〈Nch〉 ≈ 5. The two-particle correlations have been measured in terms of the angular observables cn{2} = 〈〈cosnΔφ〉〉, where n is between 1 and 4 and ∆φ is the relative azimuthal angle between the two particles. Comparisons with available models of deep inelastic scattering, which are tuned to reproduce inclusive particle production, suggest that the measured two-particle correlations are dominated by contributions from multijet production. The correlations observed here do not indicate the kind of collective behaviour recently observed at the highest RHIC and LHC energies in high-multiplicity hadronic collisions.

INFN Kids is a science education project of the Italian National Institute for Nuclear Physics addressed to young people of Primary and Middle schools age. The initiative aims at raising children’s curiosity towards science with a focus on Physics, inspiring them with science by illustrating the different research fields that INFN is pursuing, the development in technologies along with the applications in everyday life and presenting people who animate science. It gathers technicians and researchers of thirteen units and National labs in the design and realization of multimedia products, laboratory-based activities, comics, science demos and exhibits. The activities are conducted online and in person in schools, science festivals and at INFN’s sites. The adopted methodologies and the didactic tools (lectures, interactive lessons, hands-on sessions, science games) involve children in the direct exploration of natural phenomena. Given the manifold plan of activities the recipients of the project are also teachers and families, and this allowed to expand and use different formats to meet the audience’s requests. We here present an overview of the ongoing initiatives to share our experiences and we illustrate in particular the comics centered on the characters Leo and Alice that drive children in the investigation of the micro and macro world, and the laboratory-based activities designed to introduce kids some fundamental concepts related to matter and its inner structure.

Abstract The ePIC experiment at the future Electron-Ion Collider (EIC) aims to use silicon photomultipliers (SiPMs) as the photodetector technology for the dual-radiator ring-imaging Cherenkov detector (dRICH). Despite their advantages for this low light application and insensitivity to high magnetic fields, SiPMs are sensitive to radiation and require rigorous testing to ensure that their single-photon counting capabilities and dark count rate are kept under control over the years of operation. The presented results show the successful use of a complete prototype readout chain based on the ALCOR chip for SiPM characterization measurements and assembled in an optical plane for test-beam measurements using the dRICH prototype.

The design and construction of a set of parallel plate ionization chambers with one of the electrodes segmented in strips are presented. The performances of the chambers as from a test on a 270 MeV/u12C−16 beam are reported in view of their use in a 3-D dosimeter for therapeutical hadron beams.

A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarization of the electron beam was taken into account for the ZEUS data recorded between 2004 and 2007. Results on the vector and axial-vector couplings of the $Z$ boson to $u$- and $d$-type quarks, on the value of the electroweak mixing angle and the mass of the $W$ boson are presented. The values obtained for the electroweak parameters are in agreement with Standard Model predictions.

The exclusive photoproduction reactions $\gamma p \to J/\psi(1S) p$ and $\gamma p \to \psi(2S) p$ have been measured at an $ep$ centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 373 pb$^{-1}$. The measurement was made in the kinematic range $30 < W < 180$ GeV, $Q^2 < 1$ GeV$^2$ and $|t| < 1$ GeV$^2$, where $W$ is the photon--proton centre-of-mass energy, $Q^2$ is the photon virtuality and $t$ is the squared four-momentum transfer at the proton vertex. The decay channels used were $J/\psi(1S) \to \mu^+ \mu^-$, $\psi(2S) \to \mu^+ \mu^-$ and $\psi(2S) \to J/\psi(1S) \pi^+ \pi^-$ with subsequent decay $J/\psi(1S) \to \mu^+ \mu^-$. The ratio of the production cross sections, $R = \sigma_{\psi(2S)} / \sigma_{J/\psi(1S)}$, has been measured as a function of $W$ and $|t|$ and compared to previous data in photoproduction and deep inelastic scattering and with predictions of QCD-inspired models of exclusive vector-meson production, which are in reasonable agreement with the data.

The high-precision HERA data allows searches up to TeV scales for beyond the Standard Model contributions to electron–quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current ep scattering corresponding to a luminosity of around 1 fb−1 have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive ep data is presented; simultaneous fits of parton distribution functions together with contributions of “new physics” processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is 0.43⋅10−16cm.

At large values of $x$, the parton distribution functions (PDFs) of the proton are poorly constrained and there are considerable variations between different global fits. Data at such high $x$ have already been published by the ZEUS Collaboration, but not yet used in PDF extractions. A technique for comparing predictions based on different PDF sets to the observed number of events in the ZEUS data is presented. It is applied to compare predictions from the most commonly used PDFs to published ZEUS data at high Bjorken $x$. A wide variation is found in the ability of the PDFs to predict the observed results. A scheme for including the ZEUS high-$x$ data in future PDF extractions is discussed.

High-precision HERA data corresponding to a luminosity of around $1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ have been used in the framework of $eeqq$ contact interactions (CI) to set limits on possible high-energy contributions beyond the Standard Model to electron-quark scattering. Measurements of the inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering were considered. The analysis of the $ep$ data has been based on simultaneous fits of parton distribution functions including contributions of CI couplings to $ep$ scattering. Several general CI models and scenarios with heavy leptoquarks were considered. Improvements in the description of the inclusive HERA data were obtained for a few models. Since a statistically significant deviation from the Standard Model cannot be established, limits in the TeV range were set on all models considered.

Lorentz and $CPT$ symmetry in the quark sector of the Standard Model are studied in the context of an effective field theory using ZEUS ${e}^{\ifmmode\pm\else\textpm\fi{}}p$ data. Symmetry-violating effects can lead to time-dependent oscillations of otherwise time-independent observables, including scattering cross sections. An analysis using five years of inclusive neutral-current deep inelastic scattering events corresponding to an integrated HERA luminosity of $372\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ at $\sqrt{s}=318\text{ }\text{ }\mathrm{GeV}$ has been performed. No evidence for oscillations in sidereal time has been observed within statistical and systematic uncertainties. Constraints, most for the first time, are placed on 42 coefficients parametrizing dominant $CPT$-even dimension-four and $CPT$-odd dimension-five spin-independent modifications to the propagation and interaction of light quarks.

A bstract Charm production in charged current deep inelastic scattering has been measured for the first time in e ± p collisions, using data collected with the ZEUS detector at HERA, corresponding to an integrated luminosity of 358 pb −1 . Results are presented separately for e + p and e − p scattering at a centre-of-mass energy of $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 318 GeV within a kinematic phase-space region of 200 GeV 2 &lt; Q 2 &lt; 60000 GeV 2 and y &lt; 0.9, where Q 2 is the squared four-momentum transfer and y is the inelasticity. The measured cross sections of electroweak charm production are consistent with expectations from the Standard Model within the large statistical uncertainties.

The CMS and TOTEM experiments intend to carry out a joint diffractive/forward physics program with an unprecedented rapidity coverage. The present document outlines some aspects of such a physics program, which spans from the investigation of the low-x structure of the proton to the diffractive production of a SM or MSSM Higgs boson.

A search for a narrow baryonic state in the $pK^0_S$ and $\bar{p}K^0_S$ system has been performed in $ep$ collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb$^{-1}$ taken in 2003-2007. The search was performed with deep inelastic scattering events at an $ep$ centre-of-mass energy of 318 GeV for exchanged photon virtuality, $Q^2$, between 20 and 100 $\rm{} GeV^{2}$. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb$^{-1}$ taken in 1996-2000, no resonance peak was found in the $p(\bar{p})K^0_S$ invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.

The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA.Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 5 < E γ T < 15 GeV and -0.7 < η γ < 0.9, inclusively, and also with a jet with transverse energy and pseudorapidity in the ranges 4 < E jet T < 35 GeV and -1.5 < η jet < 1.8, using a total integrated electronproton luminosity of 456 pb -1 .A number of kinematic variables were studied and compared to predictions from the RAPGAP Monte Carlo model.An excess of data is observed above the RAPGAP predictions for z meas P > 0.9, where z meas P is the fraction of the longitudinal momentum of the colorless "Pomeron" exchange that is transferred to the photon-jet final state, giving evidence for direct Pomeron interactions.

A bstract Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity ep scattering at a centre-of-mass energy $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 318 GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged-particle multiplicities N ch ≥ 20 are measured. The dependence of two-particle correlations on the virtuality of the exchanged photon shows a clear transition from photoproduction to neutral current deep inelastic scattering. For the multiplicities studied, neither the measurements in photoproduction processes nor those in neutral current deep inelastic scattering indicate significant collective behaviour of the kind observed in high-multiplicity hadronic collisions at RHIC and the LHC. Comparisons of PYTHIA predictions with the measurements in photoproduction strongly indicate the presence of multiparton interactions from hadronic fluctuations of the exchanged photon.

The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering corresponding to a luminosity of around 1 fb$^{-1}$ have been used in this analysis. A approach to the beyond the Standard Model analysis of the inclusive $ep$ data is presented; simultaneous fits of parton distribution functions together with contributions of new physics processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is $0.43\cdot 10^{-16}$ cm.

A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarisation of the electron beam was taken into account for the ZEUS data recorded between 2004 and 2007. Results on the vector and axial-vector couplings of the Z boson to u- and d-type quarks, on the value of the electroweak mixing angle and the mass of the W boson are presented. The values obtained for the electroweak parameters are in agreement with Standard Model predictions.

Abstract Objective: Nuclear medicine imaging of dopamine transporter (DAT) binding is used in the differential diagnosis of neurodegenerative Parkinsonism but DAT receptor density in the posterior part of the putamens is of difficult evaluation because it is strongly affected by the partial‐volume effect. Since its quantitative correction is often difficult, we propose here a qualitative method to compare the real study to virtual images of the patient, obtained as if he/she was healthy. Method: The virtual images are obtained coregistering the magnetic resonance images to SPECT's; segmenting magnetic resonance images to obtain the real shape and position of caudates and putamens; digitally filling these volumes with an activity concentration close to normal condition; blurring and convolving images with the measured point‐spread function of the SPECT system. Result: The method was applied to phantom and, retrospectively, to a small cohort of 20 patients, that underwent SPECT examination more than 3 years ago, to prove the feasibility of the method in a clinical environment. Conclusions: This method enhances the accuracy of the nuclear medicine interpretation by the inclusion of the proper morphological information of each patient, helping the physician to differentiate between partial‐volume effects and real hypofixation of the tracer. The method proved to be feasible but is applicability is fostered by the need of a concomitant MR. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 172–176, 2012

Abstract A new measurement of inclusive-jet cross sections in the Breit frame in neutral current deep inelastic scattering using the ZEUS detector at the HERA collider is presented. The data were taken in the years 2004–2007 at a centre-of-mass energy of $$318\,\,\textrm{GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>318</mml:mn> <mml:mspace /> <mml:mspace /> <mml:mtext>GeV</mml:mtext> </mml:mrow> </mml:math> and correspond to an integrated luminosity of $$347\,\,\textrm{pb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>347</mml:mn> <mml:mspace /> <mml:mspace /> <mml:msup> <mml:mtext>pb</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . The jets were reconstructed using the $$k_t$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:math> -algorithm in the Breit reference frame. They have been measured as a function of the squared momentum transfer, $$Q^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>Q</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:math> , and the transverse momentum of the jets in the Breit frame, $$p_{\perp ,\text {Breit}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>p</mml:mi> <mml:mrow> <mml:mo>⊥</mml:mo> <mml:mo>,</mml:mo> <mml:mtext>Breit</mml:mtext> </mml:mrow> </mml:msub> </mml:math> . The measured jet cross sections are compared to previous measurements and to perturbative QCD predictions. The measurement has been used in a next-to-next-to-leading-order QCD analysis to perform a simultaneous determination of parton distribution functions of the proton and the strong coupling, resulting in a value of $$\alpha _s(M_Z^2) = 0.1142 \pm 0.0017 \text {~(experimental/fit)}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>α</mml:mi> <mml:mi>s</mml:mi> </mml:msub> <mml:mrow> <mml:mo>(</mml:mo> <mml:msubsup> <mml:mi>M</mml:mi> <mml:mi>Z</mml:mi> <mml:mn>2</mml:mn> </mml:msubsup> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>=</mml:mo> <mml:mn>0.1142</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.0017</mml:mn> <mml:mspace /> <mml:mtext>(experimental/fit)</mml:mtext> </mml:mrow> </mml:math> $${}_{-0.0007}^{+0.0006} \text {~(model/parameterisation)}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msubsup> <mml:mrow /> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.0007</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.0006</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace /> <mml:mtext>(model/parameterisation)</mml:mtext> </mml:mrow> </mml:math> $${}_{-0.0004}^{+0.0006} \text {~(scale)}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msubsup> <mml:mrow /> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.0004</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.0006</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace /> <mml:mtext>(scale)</mml:mtext> </mml:mrow> </mml:math> , whose accuracy is improved compared to similar measurements. In addition, the running of the strong coupling is demonstrated using data obtained at different scales.

The diffractive dissociation of virtual photons, gamma*p -&gt; Xp, has been studied with the H1 and ZEUS detectors at HERA using various complementary techniques. Events have been selected by direct tagging of the outgoing proton or by requiring a large rapidity gap between the proton and the system X. The diffractive contribution has also been unfolded by decomposition of the inclusive hadronic final state invariant mass distribution. Here, detailed comparisons are made between diffractive cross section measurements obtained from the different methods and the two experiments, showing them to be consistent within the large uncertainties associated with the treatment of proton dissociation processes. First steps are taken towards the combination of the H1 and ZEUS results.

The diffractive dissociation of virtual photons, gamma*p -&gt; Xp, has been studied with the ZEUS detector at HERA by requiring a large rapidity gap between X and the outgoing proton, by analysing the mass distribution, M_X, of the hadronic final state, as well as by directly tagging the proton. At low values of the proton momentum loss, the diffractive structure function measurements obtained with the three methods are consistent, provided the different treatment and contributions of proton-dissociative events are taken into account.

Isolated photons with high transverse energy have been studied in deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 326 pb−1 in the range of exchanged-photon virtuality 10-350 GeV2. Outgoing isolated photons with transverse energy 4 < E < 15 GeV and pseudorapidity − 0.7 < η γ < 0.9 were measured with accompanying jets having transverse energy and pseudorapidity 2.5 < E jet < 35 GeV and −1.5 < ηjet < 1.8, respectively. Differential cross sections are presented for the following variables: the fraction of the incoming photon energy and momentum that is transferred to the outgoing photon and the leading jet; the fraction of the incoming proton energy transferred to the photon and leading jet; the differences in azimuthal angle and pseudorapidity between the outgoing photon and the leading jet and between the outgoing photon and the scattered electron. Comparisons are made with theoretical predictions: a leading-logarithm Monte Carlo simulation, a next-to-leading-order QCD prediction, and a prediction using the k T -factorisation approach.

Recent highlights from the HERA experiments, Hermes, H1 and ZEUS, are reviewed and ideas for future analyses to fully exploit this unique data set are proposed. This document is a summary of a workshop on future physics with HERA data held at DESY, Hamburg at the end of 2014. All areas of HERA physics are covered and contributions from both experimentalists and theorists are included. The document outlines areas where HERA physics can still make a significant contribution, principally in a deeper understanding of QCD, and its relevance to other facilities. Within the framework of the Data Preservation in High Energy Physics, the HERA data have been preserved for analyses to take place over a timescale of 10 years and more. Therefore, although an extensive list of possibilities is presented here, safe storage of the data ensures that it can also be used in the far future should new ideas and analyses be proposed.

Recent measurements are discussed of inclusive and exclusive diffractive processes in pp collisions at √ s = 7 TeV at the LHC using the CMS detector.Results are presented of the singleand double-diffractive cross section and of the inclusive differential cross section for events with a forward rapidity gap.A study of exclusive W + W -production by two-photon exchange, where, in different kinematic regions, both confirmation and deviations from the Standard Model predictions are searched, is reported.Finally, a joint measurement with the CMS and TOTEM detectors of the pseudorapidity distribution of charged particles produced in pp collisions at √ s = 8 TeV is presented.This is the first joint study between the two experiments.

on behalf of the CMS Collaboration)

Recent highlights from the HERA experiments, Hermes, H1 and ZEUS, are reviewed and ideas for future analyses to fully exploit this unique data set are proposed. This document is a summary of a workshop on future physics with HERA data held at DESY, Hamburg at the end of 2014. All areas of HERA physics are covered and contributions from both experimentalists and theorists are included. The document outlines areas where HERA physics can still make a significant contribution, principally in a deeper understanding of QCD, and its relevance to other facilities. Within the framework of the Data Preservation in High Energy Physics, the HERA data have been preserved for analyses to take place over a timescale of 10 years and more. Therefore, although an extensive list of possibilities is presented here, safe storage of the data ensures that it can also be used in the far future should new ideas and analyses be proposed.

A combination is presented of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA. The analysis uses samples of diffractive deep inelastic scattering data where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account by the combination method, resulting in improved precision.

The aim of this document is to introduce to the CMS Upgrade Committee the High Precision Spectrometer (HPS), a proposed sub-detector for CMS, and to outline an 18-month R&D project to address several technical issues related to the first stage of HPS.

Isolated photons with high transverse energy have been studied in deep inelastic $ep$ scattering with the ZEUS detector at HERA, using an integrated luminosity of $326\,$ pb$^{-1}$ in the range of exchanged-photon virtuality $10 - 350$ GeV$^2$. Outgoing isolated photons with transverse energy $4<E_T^\gamma< 15$ GeV and pseudorapidity $-0.7 <\eta^\gamma< 0.9$ were measured with accompanying jets having transverse energy and pseudorapidity $2.5 <E_T^{jet}<35$ GeV and $-1.5<\eta^{jet}< 1.8$, respectively. Differential cross sections are presented for the following variables: the fraction of the incoming photon energy and momentum that is transferred to the outgoing photon and the leading jet; the fraction of the incoming proton energy transferred to the photon and leading jet; the differences in azimuthal angle and pseudorapidity between the outgoing photon and the leading jet and between the outgoing photon and the scattered electron. Comparisons are made with theoretical predictions: a leading-logarithm Monte Carlo simulation, a next-to-leading-order QCD prediction, and a prediction using the $k_T$-factorisation approach.

The LHC FP420 R&D project is assessing the feasibility of installing forward proton detectors at 420m from the ATLAS and/or CMS interaction points. Such detectors aim at measuring diffracted protons, which have lost less than 2% of their longitudinal momentum. The success of this measurement requires a very good understanding of the charged and neutral particle environment in the detector region in order to avoid the signal being swamped as well as for detector survivability. This background receives contributions from beam-gas interactions, halo particles surviving from the betatron and momentum cleaning systems and secondary showers produced by particles from the 14 TeV collision region striking the beampipe upstream of the FP420 detectors. In this paper, such background sources are reviewed, and the expected background rates calculated. INTRODUCTION TO FP420 The FP420 R&D project [1] aims at exploring the immense amount of LHC physics potential by instrumenting with detectors the forward regions starting at about 420 m from IP1 and IP5. The tag on one or both of the forward protons can provide information on the mass of the central system in the detector and allowing measurements of quantities like the mass and quantum numbers of the Higgs Boson. This experimental programme would add considerable depth and potential to the main detector experimental programmes. The proposed detectors consist of tracking and timing stations, mounted on movable beam pipes, approaching the beam as close as allowed by LHC protection/ beam stability and as required by the experiment acceptance studies. The present proposed setup is at a horizontal distance of 5mm from the beam. CLASSIFICATIONS OF BACKGROUND The charged and neutral particle backgrounds at 420m can be classified according to the origin of the particle flux: 1) At the interaction point, the colliding beams produce many final state protons dominantly in the forward direction with a large coverage of phase space. These particles may be transported down the beamline and irradiate the 420m region. This contribution to the background is referred to as interaction point (IP) particles. 2) Elastic and inelastic proton-nucleus collisions between ∗Work supported by STFC, UK † robert.appleby@manchester.ac.uk the beam and residual gas molecules resulting in protons with large scattering angles represent a direct background when the collisions occur close to the FP420 detector stations. This is referred to as the near beam-gas background. 3) Beam halo consists of protons in the distribution tails that can circulate for many turns and constitute the beam halo background. The primary halo is populated by various beam instabilities including distant beam-gas interactions resulting in small scattering angle protons. The consequent beam losses on both the betatron and momentum cleaning collimation systems produce secondary and tertiary halos. 4) Particles transported down the beam line arising from proton-proton interactions at the IP, near beam-gas collisions or any other beam-halo, can interact, and subsequently shower, with elements of the machine or detector. These processes create secondary showers which can irradiate the detector region at 420m with large charged and neutral particle fluxes. This background is known as secondary interactions. In this paper, the present status of each background source at 420m is reviewed and the possible impact on the detector assessed. IMPACT OF BACKGROUND SOURCES Near Beam-gas Interactions The near beam-gas contribution arises from the interaction of beam particles with residual gas in the beam pipe region immediately before 420 m, and study of this background requires a detailed model of the beam line, coupled with gas pressure profiles and computation of proton/gas interactions. However, an estimate of the number of beamgas interactions per bunch in the 420 m detector region can be extracted by scaling results obtained for the straight section [2]. These simulations give a charged hadron rate for particles lost after scattering with the gas nuclei and secondary particles as np240 m = 2.4 s−1, at a location 240m from IP1. The Hydrogen equivalent pressure is taken to be [2, 3] ρ240 m = 3.4 · 10 molecules ·m−3. The synchrotron radiation at 420m implies that the dynamic pressure is higher than the straight sections and, as a conservative upper limit, we consider a hydrogen density of ρ420 m = 1 · 10 molecules · m−3 This corresponds to a beam-gas lifetime of 100 hours. The resulting total number of expected hadrons per bunch, due to near beam-gas events, is around np420 m = np240 m Nbs · ρ420 m ρ240 m = 1.8 · 10−4, (1) Proceedings of EPAC08, Genoa, Italy MOPP006 04 Hadron Accelerators A04 Circular Accelerators

More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given.

The differential diagnosis of Parkinson desease versus other forms of pakinsonism is not easy to be achieved. Imaging of dopamine transporter binding by means of nuclear medicine techniques is often used to improve the probability of a correct diagnosis in the early stages. Crucial for this kind of studies is the correct determination of the dopamine transporter receptor density in the posterior part of the putamens. Unfortunately, tomographic images of these structures are strongly affected by the partial-volume effect (PVE). Since its correction is often tricky and difficult to realize, we propose here a method in which the nuclear medicine study is compared to virtual images derived from MRI. This method enhances the accuracy of the nuclear medicine procedure, helping the physician to differentiate between partial-volume effects and real hypofixation of the tracer, in particular in the early phase of the disease.

The diffractive dissociation of virtual photons, gamma*p -> Xp, has been studied with the H1 and ZEUS detectors at HERA using various complementary techniques. Events have been selected by direct tagging of the outgoing proton or by requiring a large rapidity gap between the proton and the system X. The diffractive contribution has also been unfolded by decomposition of the inclusive hadronic final state invariant mass distribution. Here, detailed comparisons are made between diffractive cross section measurements obtained from the different methods and the two experiments, showing them to be consistent within the large uncertainties associated with the treatment of proton dissociation processes. First steps are taken towards the combination of the H1 and ZEUS results.

More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given.

Charm production in charged current deep inelastic scattering has been measured for the first time in $e^{\pm}p$ collisions, using data collected with the ZEUS detector at HERA, corresponding to an integrated luminosity of $358 pb^{-1}$. Results are presented separately for $e^{+}p$ and $e^{-}p$ scattering at a centre-of-mass energy of $\sqrt{s} = 318 GeV$ within a kinematic phase-space region of $200 GeV^{2}<Q^{2}<60000 GeV^{2}$ and $y<0.9$, where $Q^{2}$ is the squared four-momentum transfer and $y$ is the inelasticity. The measured cross sections of electroweak charm production are consistent with expectations from the Standard Model within the large statistical uncertainties.

Abstract

Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity $ep$ scattering at a centre-of-mass energy $\sqrt{s}=318$ GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged-particle multiplicities $N_{\textrm{ch}} \geq 20$ are measured. The dependence of two-particle correlations on the virtuality of the exchanged photon shows a clear transition from photoproduction to neutral current deep inelastic scattering. For the multiplicities studied, neither the measurements in photoproduction processes nor those in neutral current deep inelastic scattering indicate significant collective behaviour of the kind observed in high-multiplicity hadronic collisions at RHIC and the LHC. Comparisons of PYTHIA predictions with the measurements in photoproduction strongly indicate the presence of multiparton interactions from hadronic fluctuations of the exchanged photon.

The diffractive dissociation of virtual photons, gamma*p -&gt; Xp, has been studied in ep interactions at HERA with the H1 and ZEUS detectors. The data are presented in terms of the diffractive structure function F2D and of the diffractive cross sections dsigma/dt and dsigma/dMX. The t-dependence of the cross section is measured. The Pomeron intercepts extracted from diffractive and inclusive ep interactions are compared. The result is further interpreted studying the dependence of the ratio between the diffractive to the inclusive cross section on the photon-proton center of mass energy. Recent data on the Q2 dependence of the diffractive cross section at 0.17 &lt; Q2 &lt; 0.70 GeV2 constrain the transition in diffraction from the perturbative high Q2 region to the photoproduction limit.