Aysel Kayiş Topaksu

The double-differential production cross-section of positive pions, $d^2\sigma^{\pi^{+}}/dpd\Omega$, measured in the HARP experiment is presented. The incident particles are 8.9 GeV/c protons directed onto a beryllium target with a nominal thickness of 5% of a nuclear interaction length. The measured cross-section has a direct impact on the prediction of neutrino fluxes for the MiniBooNE and SciBooNE experiments at Fermilab. After cuts, 13 million protons on target produced about 96,000 reconstructed secondary tracks which were used in this analysis. Cross-section results are presented in the kinematic range 0.75 GeV/c < $p_{\pi}$ < 6.5 GeV/c and 30 mrad < $\theta_{\pi}$ < 210 mrad in the laboratory frame.

We report on the test beam results and calibration methods using high energy electrons, pions and muons with the CMS forward calorimeter (HF). The HF calorimeter covers a large pseudorapidity region ( $3\leq|\eta|\leq5$ ), and is essential for a large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of forward tagging jets in weak boson fusion channels in Higgs production. The HF calorimeter is based on steel absorber with embedded fused-silica-core optical fibers where Cherenkov radiation forms the basis of signal generation. Thus, the detector is essentially sensitive only to the electromagnetic shower core and is highly non-compensating (e/h≈5). This feature is also manifest in narrow and relatively short showers compared to similar calorimeters based on ionization. The choice of fused-silica optical fibers as active material is dictated by its exceptional radiation hardness. The electromagnetic energy resolution is dominated by photoelectron statistics and can be expressed in the customary form as $\frac{a}{\sqrt{E}}\oplus{b}$ . The stochastic term a is 198% and the constant term b is 9%. The hadronic energy resolution is largely determined by the fluctuations in the neutral pion production in showers, and when it is expressed as in the electromagnetic case, a = 280% and b = 11%.

The nuclear emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy from 1994 to 1997. In total, about 100 000 charged-current (CC) neutrino interactions with at least one identified muon were located in the emulsion target and fully reconstructed, using newly developed automated scanning systems. Charmed particles were searched for by a program recognizing particle decays. The observation of the decay in nuclear emulsion makes it possible to select a sample with very low background and minimal kinematical bias. In all, 2013 CC interactions with a charmed hadron candidate in the final state were selected and confirmed through visual inspection. The charm production rate induced by neutrinos relative to the CC cross-section is measured to be σ(νμN→μ−CX)/σ(CC)=(5.75 ± 0.32(stat)±0.30(syst))%. The charm production cross-section as a function of neutrino energy is also obtained. The results are in good agreement with previous measurements. The charm-quark hadronization produces the following charmed hadrons with relative fractions (in %): fD0=43.7±4.5, fΛc+=19.2±4.2, fD+=25.3±4.2 and fDs+=11.8±4.7.

A precision measurement of the double-differential production cross-section, d2σπ+/dpdΩ, for pions of positive charge, performed in the HARP experiment is presented. The incident particles are protons of 12.9 GeV/c momentum impinging on an aluminium target of 5% nuclear interaction length. The measurement of this cross-section has a direct application to the calculation of the neutrino flux of the K2K experiment. After cuts, 210 000 secondary tracks reconstructed in the forward spectrometer were used in this analysis. The results are given for secondaries within a momentum range from 0.75 to 6.5 GeV/c, and within an angular range from 30 mrad to 210 mrad. The absolute normalization was performed using prescaled beam triggers counting protons on target. The overall scale of the cross-section is known to better than 6%, while the average point-to-point error is 8.2%.

HARP is a high-statistics, large solid angle experiment to measure hadron production using proton and pion beams with momenta between 1.5 and 15 GeV/c impinging on many different solid and liquid targets from low to high Z. The experiment, located in the T9 beam of the CERN PS, took data in 2001 and 2002. For the measurement of momenta of produced particles and for the identification of particle types, the experiment includes a large-angle spectrometer, based on a Time Projection Chamber and a system of Resistive Plate Chambers, and a forward spectrometer equipped with a set of large drift chambers, a threshold Cherenkov detector, a time-of-flight wall and an electromagnetic calorimeter. The large angle system uses a solenoidal magnet, while the forward spectrometer is based on a dipole magnet. Redundancy in particle identification has been sought, to enable the cross-calibration of efficiencies and to obtain a few percent overall accuracy in the cross-section measurements. Detector construction, operation and initial physics performances are reported. In addition, the full chain for data recording and analysis, from trigger to the software framework, is described.

Measurements of the double-differential π± production cross section in the momentum range 100⩽p⩽800 MeV/c and angle range 0.35⩽θ⩽2.15 rad in proton-beryllium, proton-carbon, proton-aluminium, proton-copper, proton-tin, proton-tantalum, and proton-lead collisions are presented. The data were taken with the large-acceptance HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 to 12.9 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. Tracking and identification of the produced particles was performed by using a small-radius cylindrical Time Projection Chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross sections d2σ/(dpdθ) at six incident proton beam momenta [3, 5, 8, and 8.9 GeV/c (Be only) and 12 and 12.9 GeV/c (Al only)]. They are based on a complete correction of static and dynamic distortions of tracks in the HARP TPC, which allows the complete statistics of the collected data set to be used. The results include and supersede our previously published results and are compatible with these. Results are compared with the GEANT4 and MARS Monte Carlo simulation.26 MoreReceived 27 December 2007DOI:https://doi.org/10.1103/PhysRevC.77.055207©2008 American Physical Society

The final oscillation analysis of the complete set of data collected by CHORUS in the years 1994–1997 is presented. Reconstruction algorithms of data extracted by electronic detectors were improved and the data recorded in the emulsion target were analysed by new automated scanning systems, allowing the use of a new method for event reconstruction in emulsion. CHORUS has applied these new techniques to the sample of 1996–1997 events for which no muons were observed in the electronic detectors. Combining the new sample with the data analysed in previous papers, the overall sensitivity of the experiment to the ντ appearance is thus improved. In a two-neutrino mixing scheme, a 90% C.L. upper limit of sin22θμτ<4.4×10−4 is set for large Δm2, improving by a factor 1.5 the previously published CHORUS result.

Extensive measurements have been made with pions, electrons and muons on four production wedges of the compact muon solenoid (CMS) hadron barrel (HB) calorimeter in the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics running at 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers in the HB. The energy dependent time slewing effect was measured and tuned for optimal performance.

In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of $5\%$ for signal and $10\%$ for background, we find that there is $10\sigma$ $(13\sigma)$ CP violation discovery sensitivity for the baseline option of 540 km (360 km) at $\delta_{\rm CP} = \pm 90^\circ$. The corresponding fraction of $\delta_{\rm CP}$ for which CP violation can be discovered at more than $5 \sigma$ is $70\%$. Regarding CP precision measurements, the $1\sigma$ error associated with $\delta_{\rm CP} = 0^\circ$ is around $5^\circ$ and with $\delta_{\rm CP} = -90^\circ$ is around $14^\circ$ $(7^\circ)$ for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have $3\sigma$ sensitivity for 540 km baseline except $\delta_{\rm CP} = \pm 90^\circ$ and $5\sigma$ sensitivity for 360 km baseline for all values of $\delta_{\rm CP}$. The octant of $\theta_{23}$ can be determined at $3 \sigma$ for the values of: $\theta_{23} > 51^\circ$ ($\theta_{23} < 42^\circ$ and $\theta_{23} > 49^\circ$) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at $3 \sigma$ are: $40^\circ < \theta_{23} < 52^\circ$ ($42^\circ < \theta_{23} < 51.5^\circ$) and $2.485 \times 10^{-3}$ eV$^2 < \Delta m^2_{31} < 2.545 \times 10^{-3}$ eV$^2$ ($2.49 \times 10^{-3}$ eV$^2 < \Delta m^2_{31} < 2.54 \times 10^{-3}$ eV$^2$) for the baseline of 540 km (360 km).

A measurement of the double-differential cross-section for the production of charged pions in proton--tantalum collisions emitted at large angles from the incoming beam direction is presented. The data were taken in 2002 with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \GeVc to 12 \GeVc hitting a tantalum target with a thickness of 5% of a nuclear interaction length. The angular and momentum range covered by the experiment ($100 \MeVc \le p < 800 \MeVc$ and $0.35 \rad \le \theta <2.15 \rad$) is of particular importance for the design of a neutrino factory. The produced particles were detected using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. Track recognition, momentum determination and particle identification were all performed based on the measurements made with the TPC. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections ${{\mathrm{d}^2 \sigma}} / {{\mathrm{d}p\mathrm{d}\theta}}$ at four incident proton beam momenta (3 \GeVc, 5 \GeVc, 8 \GeVc and 12 \GeVc). In addition, the pion yields within the acceptance of typical neutrino factory designs are shown as a function of beam momentum. The measurement of these yields within a single experiment eliminates most systematic errors in the comparison between rates at different beam momenta and between positive and negative pion production.

We present a leading order QCD analysis of a sample of neutrino induced charged-current events with two muons in the final state originating in the lead-scintillating fibre calorimeter of the CHORUS detector. The results are based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign dimuon events collected during the exposure of the detector to the CERN Wide Band Neutrino Beam between 1995 and 1998. % with $E_{\mu 1},E_{\mu 2} > 5$ GeV and $Q^2 > 3$ GeV$^2$ collected %between 1995 and 1998. The analysis yields a value of the charm quark mass of $\mc = (1.26\pm 0.16 \pm 0.09) \GeVcc $ and a value of the ratio of the strange to non-strange sea in the nucleon of $\kappa = 0.33 \pm 0.05 \pm 0.05$, improving the results obtained in similar analyses by previous experiments.

We present performance studies of a full-length prototype for the CASTOR quartz-tungsten sampling calorimeter, installed in the very forward region of the CMS experiment at the LHC. The response linearity and energy resolution, the uniformity, as well as the showers’ spatial properties in the prototype have been studied with electrons, pions and muons of various energies. A special study was also carried out for testing the light-output with a 90-degree cut of the quartz plates of the calorimeter. The data were taken during the CASTOR test beam at CERN/SPS in 2007.

The results of the measurements of the double-differential production cross-sections of pions in p-C and $\pi^\pm$-C interactions using the forward spectrometer of the HARP experiment are presented. The incident particles are 12 GeV/c protons and charged pions directed onto a carbon target with a thickness of 5% of a nuclear interaction length. For p-C interactions the analysis is performed using 100035 reconstructed secondary tracks, while the corresponding numbers of tracks for $\pi^-$-C and $\pi^+$-C analyses are 106534 and 10122 respectively. Cross-section results are presented in the kinematic range 0.5 GeV/c $\leq p_{\pi} <$ 8 GeV/c and 30 mrad $\leq \theta_{\pi} <$ 240 mrad in the laboratory frame. The measured cross-sections have a direct impact on the precise calculation of atmospheric neutrino fluxes and on the improved reliability of extensive air shower simulations by reducing the uncertainties of hadronic interaction models in the low energy range.

A measurement of the double-differential π± production cross-section in proton–carbon, proton–copper and proton–tin collisions in the range of pion momentum 100 MeV/c≤p<800 MeV/c and angle 0.35 rad≤θ<2.15 rad is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections d2σ/dpdθ at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c).

Measurements of the double-differential charged pion production cross-section in the range of momentum 0.5 GeV/c < p < 8.0 GeV/c and angle 0.025 rad < theta <0.25 rad in collisions of protons on beryllium, carbon, nitrogen, oxygen, aluminium, copper, tin, tantalum and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. Incident particles were identified by an elaborate system of beam detectors. The data were taken with thin targets of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using the forward system of the HARP experiment. Results are obtained for the double-differential cross section mainly at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). Measurements are compared with the GEANT4 and MARS Monte Carlo generators. A global parametrization is provided as an approximation of all the collected datasets which can serve as a tool for quick yields estimates.

From 1994 to 1997, the emulsion target of the CHORUS detector was exposed to the wideband neutrino beam of the CERN SPS. In total about 100 000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. From this sample of events based on the data acquired by new automatic scanning systems, 2013 charm-decay events were selected by a pattern recognition program. They were confirmed as decays through visual inspection. Based on these events, the effective branching ratio of charmed particles into muons was determined to be B¯μ=[7.3±0.8(stat)±0.2(syst)]×10−2. In addition, the muonic branching ratios are presented for dominating charm-decay topologies. Normalization of the muonic decays to charged-current interactions provides σμ−μ+/σcc=[3.16±0.34(stat)±0.09(syst)]×10−3. Selecting only events with visible energy greater than 30 GeV gives a value of B¯μ that is less affected by the charm production threshold and quasi-elastic Λc+ production. Combining this value with the current average of B¯μ×|Vcd|2 at the leading order yields the value of |Vcd|LO=0.236±0.016.

Measurements of the double-differential π± production cross-section in the range of momentum 100 MeV/c≤p< 800 MeV/c and angle 0.35 rad ≤θ< 2.15 rad in proton–beryllium, proton–aluminium and proton–lead collisions are presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12.9 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections d2σ/dpdθ at six incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c, 8.9 GeV/c (Be only), 12 GeV/c and 12.9 GeV/c (Al only)) and compared to previously available data.

During the years 1994–1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy. In total about 100 000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. From this sample of events which was based on the data acquired by new automatic scanning systems, 1048 charged-current interactions with a D0 in the final state were selected by a pattern recognition program and confirmed as neutral-particle decays through visual inspection. The ratio of decay branching fractions of the D0 into four charged particles to two charged particles was measured to be B(D0→V4)/B(D0→V2)=0.207±0.016±0.004. The inclusive measurement of the observed production rate of the D0 with a decay into four charged prongs in combination with external measurements of this topological branching ratio was used to determine the total D0 production rate by neutrinos without additional assumption on the branching fractions. The value of this rate relative to the charged-current cross-section was found to be σ(D0)/σ(CC)=0.0269±0.0018±0.0013. In addition, the same normalization method was used to deduce the inclusive topological decay rate into final states with neutral particles only. A value of 0.218±0.049±0.036 was found for this branching fraction. From an observed number of three charged six-prong events the branching ratio into six charged particles was determined to be (1.2−0.9+1.3±0.2)×10−3. A measurement of the energy dependence of the D0 production by neutrinos relative to the total charged-current cross-section is also reported. This measurement was used to deduce for mc, the effective charm-quark mass, a value of (1.42±0.08)GeV/c2.

Measurements of the double-differential π± production cross-section in the range of momentum 0.5 GeV/c⩽p⩽8.0 GeV/c and angle 0.025rad⩽θ⩽0.25rad in interactions of charged pions on beryllium, carbon, aluminium, copper, tin, tantalum and lead are presented. These data represent the first experimental campaign to systematically measure forward pion hadroproduction. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. Incident particles, impinging on a 5% nuclear interaction length target, were identified by an elaborate system of beam detectors. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP detector. Results are obtained for the double-differential cross-sections d2σ/dpdΩ mainly at four incident pion beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). The measurements are compared with the GEANT4 and MARS Monte Carlo simulation.

Measurements of the double-differential pi+/- production cross-section in the range of momentum 100 MeV/c <= p <= 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad using pi+/- beams incident on beryllium, aluminium, carbon, copper, tin, tantalum and lead targets are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN Proton Synchrotron. The secondary pions were produced by beams in a momentum range from 3 GeV/c to 12.9 GeV/c hitting a solid target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections d2sigma/dpdtheta at six incident beam momenta. Data at 3 GeV/c, 5 GeV/c, 8 GeV/c, and 12 GeV/c are available for all targets while additional data at 8.9 GeV/c and 12.9 GeV/c were taken in positive particle beams on Be and Al targets, respectively. The measurements are compared with several generators of GEANT4 and the MARS Monte Carlo simulation.

We report on a search for associated charm production in neutrino charged-current interactions in the CHORUS experiment, based on the visual observation of charmed-particle decays. The search differs from those carried out so far in which the production of cc̄ has been inferred from measurements of events with two or three muons in the final state, resulting from the decay of charmed hadrons. One event with a double charm-decay topology has been found and a corresponding background of 0.04 events has been evaluated.

A study of quasi-elastic production of charmed baryons in charged-current interactions of neutrinos with the nuclear emulsion target of CHORUS is presented. In a sample of about 46 000 interactions located in the emulsion, candidates for decays of short-lived particles were identified by using new automatic scanning systems and later confirmed through visual inspection. Criteria based both on the topological and kinematical characteristics of quasi-elastic charm production allowed a clear separation between events of this type and those in which charm is produced in deep inelastic processes. A final sample containing 13 candidates consistent with quasi-elastic production of a charmed baryon with an estimated background of 1.7 events was obtained. At the average neutrino energy of 27 GeV the cross-section for the total quasi-elastic production of charmed baryons relative to the νN charged-current cross-section was measured to be σ(QE)/σ(CC)=(0.23+0.12−0.06(stat)+0.02−0.03(syst))×10−2. Through an analysis of the topology at the production and decay vertices the relative cross-sections were measured separately for singly (Λc+,Σc+,Σc+∗) and doubly (Σc++,Σc++∗) charged baryons.

The particle identification (PID) methods used for the calculation of secondary pion yields with the HARP forward spectrometer are presented. Information from time of flight and Cherenkov detectors is combined using likelihood techniques. The efficiencies and purities associated with the different PID selection criteria are obtained from the data. For the proton–aluminium interactions at 12.9 GeV/c incident momentum, the PID efficiencies for positive pions are 86% in the momentum range below 2 GeV/c, 92% between 2 and 3 GeV/c and 98% in the momentum range above 3 GeV/c. The purity of the selection is better than 92% for all momenta. Special emphasis has been put on understanding the main error sources. The final PID uncertainty on the pion yield is 3.3%.

Measurements of double-differential charged pion production cross-sections in interactions of 12 GeV/c protons on O_2 and N_2 thin targets are presented in the kinematic range 0.5 GeV/c < p_{\pi} < 8 GeV/c and 50 mrad < \theta_{\pi} < 250 mrad (in the laboratory frame) and are compared with p--C results. For p--N_2 (p--O_2) interactions the analysis is performed using 38576 (7522) reconstructed secondary pions. The analysis uses the beam instrumentation and the forward spectrometer of the HARP experiment at CERN PS. The measured cross-sections have a direct impact on the precise calculation of atmospheric neutrino fluxes and on the improved reliability of extensive air shower simulations by reducing the uncertainties of hadronic interaction models in the low energy range. In particular, the present results allow the common hypothesis that p--C data can be used to predict the p--N_2 and p--O_2 pion production cross-sections to be tested.

During the years 1994–1997, the emulsion target of the CHORUS detector was exposed to the CERN-SPS Wide Band Neutrino Beam. The improvements of the past few years in the automatic emulsion scanning systems allowed a sample of events located in emulsion to be used for studies of charm production. Based on a sample of 56172νμ charged-current interactions analysed so far, we find a value of Bμ=0.093±0.009(stat.)±0.009(syst.) for the semi-leptonic branching fraction of charm hadrons. The result for events with visible energy larger than 30 GeV, Bμ=0.102±0.016(stat.)±0.010(syst.), can be combined with the existing measurements of the dimuon rate to yield a value of 0.219±0.022 for the magnitude of the Cabibbo–Kobayashi–Maskawa matrix element |Vcd|.

During the years 1994–1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS. In total about 100 000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. From this sample of events which was based on the data acquired by new automatic scanning systems, 1048 D0 events were selected by a pattern recognition program. They were confirmed as neutral-particle decays through visual inspection. Fragmentation properties of deep-inelastic charm production were measured using these events. Distributions of the D0 momentum, Feynman x (xF), z and tanθout, the transverse angle out of the leptonic plane defined by the muon and the neutrino, are presented. The mean value of z was measured to be 〈z〉=0.63±0.03(stat)±0.01(syst). From fits to the z distribution, values for the Peterson parameter εP=0.108±0.017(stat)±0.013(syst) and the Collins–Spiller parameter εCS=0.21−0.04+0.05(stat)±0.04(syst) are found. For the average value of xF we find 〈xF〉=0.38±0.04(stat)±0.03(syst) and for the forward–backward asymmetry A=0.79±0.14(stat)±0.05(syst). The distribution of tanθout was measured with an average value 〈tanθout〉=0.030±0.002.

In this paper a search for associated charm production both in neutral and charged current $\nu$-nucleus interactions is presented. The improvement of automatic scanning systems in the {CHORUS} experiment allows an efficient search to be performed in emulsion for short-lived particles. Hence a search for rare processes, like the associated charm production, becomes possible through the observation of the double charm-decay topology with a very low background. About 130,000 $\nu$ interactions located in the emulsion target have been analysed. Three events with two charm decays have been observed in the neutral-current sample with an estimated background of 0.18$\pm$0.05. The relative rate of the associated charm cross-section in deep inelastic $\nu$ interactions, $\sigma(c\bar{c}\nu)/\sigma_\mathrm{NC}^\mathrm{DIS}= (3.62^{+2.95}_{-2.42}({stat})\pm 0.54({syst}))\times 10^{-3}$ has been measured. One event with two charm decays has been observed in charged-current $\nu_\mu$ interactions with an estimated background of 0.18$\pm$0.06 and the upper limit on associated charm production in charged-current interactions at 90% C.L. has been found to be $\sigma (c\bar{c} \mu^-)/\sigma_\mathrm{CC} < 9.69 \times 10^{-4}$.

The CHORUS experiment, designed to search for νμ→ντ oscillations, consists of a nuclear emulsion target and electronic detectors. In this paper, results on the production of charged particles in a small sample of charged-current neutrino– and anti-neutrino–nucleus interactions at high energy are presented. For each event, the emission angle and the ionization features of the charged particles produced in the interaction are recorded, while the standard kinematic variables are reconstructed using the electronic detectors. The average multiplicities for charged tracks, the pseudo-rapidity distributions, the dispersion in the multiplicity of charged particles and the KNO scaling are studied in different kinematical regions. A study of quasi-elastic topologies performed for the first time in nuclear emulsions is also reported. The results are presented in a form suitable for use in the validation of Monte Carlo generators of neutrino–nucleus interactions.

In the HARP experiment the large-angle spectrometer is using a cylindrical TPC as main tracking and particle identification detector. The momentum scale of reconstructed tracks in the TPC is the most important systematic error for the majority of kinematic bins used for the HARP measurements of the double-differential production cross-section of charged pions in proton interactions on nuclear targets at large angle. The HARP TPC operated with a number of hardware shortfalls and operational mistakes. Thus it was important to control and characterize its momentum calibration. While it was not possible to enter a direct particle beam into the sensitive volume of the TPC to calibrate the detector, a set of physical processes and detector properties were exploited to achieve a precise calibration of the apparatus. In the following we recall the main issues concerning the momentum measurement in the HARP TPC, and describe the cross-checks made to validate the momentum scale. As a conclusion, this analysis demonstrates that the measurement of momentum is correct within the published precision of 3%.

Measurements of the double-differential proton production cross-section ${d}^{2}\ensuremath{\sigma}/dpd\ensuremath{\Omega}$ in the range of momentum $0.5 \mathrm{GeV}/c\ensuremath{\leqslant}p&lt;8.0 \mathrm{GeV}/c$ and angle $0.05 \text{rad}\ensuremath{\leqslant}\ensuremath{\theta}&lt;0.25 \text{rad}$ in collisions of charged pions and protons on beryllium, carbon, aluminium, copper, tin, tantalum, and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN Proton Synchrotron. Incident particles were identified by an elaborate system of beam detectors and impinged on a target of $5%$ of a nuclear interaction length. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP experiment. Results are obtained for the double-differential cross-sections mainly at four incident beam momenta ($3,5,8$, and $12$ $\text{GeV}/c$). Measurements are compared with predictions of the geant4 and mars Monte Carlo generators.

Observation of J/ψ production by neutrinos in the calorimeter of the CHORUS detector exposed to the CERN SPS wide-band νμ beam is reported. A spectrum-averaged cross section σJ/ψ=(6.3±3.0)×10−41 cm2 is obtained for 20 GeV ⩽Eν⩽ 200 GeV. The data are compared with the theoretical model based on the QCD Z-gluon fusion mechanism.

During the years 1994–1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy. In total about 100 000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. A high-statistics sample of neutrino interactions with a D0 in the final state was collected. Using the decay mode D*+→D0π+ a production cross-section measurement of the D*+ in neutrino–nucleon charged-current interactions was performed. The low Q-value of the decay was used to isolate a sample of candidate events containing a positive hadron with a small pT with respect to the D0 direction. A signal of 22.1±5.5D*+ events was obtained. The D*+ production cross-section relative to the D0 production cross-section, σ(D*+)/σ(D0), was estimated to be 0.38±0.09(stat)±0.05(syst). From this result, the fraction of D0's produced via the decay of a D* was deduced to be 0.63±0.17. The D*+ production cross-section relative to the νμ charged-current interaction, σ(D*+)/σ(CC), was estimated to be [1.02±0.25(stat)±0.15(syst)]%.

This Letter reports on a study of trimuon events induced by neutrino interactions in the CHORUS calorimeter exposed to the CERN SPS wide-band νμ beam. Among the multimuon events produced in the calorimeter, 42 μ−μ−μ+ events were selected and their kinematical properties investigated. In the past, several groups collected a sample of about one hundred events of this type but their source was largely unknown. Taking advantage of experimental data presently available on the production and muonic branching ratios of light neutral mesons and resonances, we make absolute predictions for the expected rates in our experiment. Detailed Monte Carlo simulations described in this article show that more than half of the trimuon events can be attributed to this source. Muons from π− and K− decays in charm dimuon events are responsible for an additional ≈25% contribution to the total μ−μ−μ+ rate. The remaining 25% of events are likely to come from the internal bremsstrahlung of virtual photons into a muon pair. Associated-charm production with subsequent decays of both charmed particles into muons is a negligible source of trimuon events.

The HARP Collaboration has presented measurements of the double-differential ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ production cross section in the range of momentum $100 \text{MeV}/c\ensuremath{\leqslant}p\ensuremath{\leqslant}800 \text{MeV}/c$ and angle $0.35 \text{rad}\ensuremath{\leqslant}\ensuremath{\theta}\ensuremath{\leqslant}2.15 \text{rad}$ with proton beams hitting thin nuclear targets. In many applications the extrapolation to long targets is necessary. In this article the analysis of data taken with long (one interaction length) solid cylindrical targets made of carbon, tantalum, and lead is presented. The data were taken with the large-acceptance HARP detector in the T9 beam line of the CERN proton synchrotron. The secondary pions were produced by beams of protons with momenta of 5, 8, and $12\text{GeV}/c$. The tracking and identification of the produced particles were performed using a small-radius cylindrical time projection chamber placed inside a solenoidal magnet. Incident protons were identified by an elaborate system of beam detectors. Results are obtained for the double-differential yields per target nucleon ${\mathrm{d}}^{2}\ensuremath{\sigma}/\mathrm{d}p\mathrm{d}\ensuremath{\theta}$. The measurements are compared with predictions of the MARS and GEANT4 Monte Carlo simulations.

After measuring in 2012 a relatively large value of the neutrino mixing angle θ 13 , the door is now open to observe for the first time a possible CP violation in the leptonic sector.The measured value of θ 13 also privileges the 2nd oscillation maximum for the discovery of CP violation instead of the usually used 1st oscillation maximum.The sensitivity at this 2nd oscillation maximum is significantly higher than for the 1st oscillation maximum also inducing a lower influence of systematic errors.Going to the 2nd oscillation maximum necessitates a very intense neutrino beam with the appropriate energy.The world's most intense pulsed neutron source, the European Spallation Source, will have a proton linac with 5 MW power and 2 GeV energy.This linac, under construction, also has the potential to become the proton driver of the world's most intense neutrino beam with very high potential to discover a neutrino CP violation.The physics performance of that neutrino Super Beam in conjunction with a megaton underground Water Cherenkov neutrino detector installed at a distance of about 500 km from ESS has been evaluated.In addition, the choice of such detector will extent the physics program to proton-decay, atmospheric neutrinos and astrophysics searches.The ESS proton linac upgrades, the accumulator ring needed for proton pulse compression, the Target Station and the physics potential are described.In addition to neutrinos, this facility will also produce at the same time a copious number of muons which could be used by other physics applications.The ESS linac will be fully ready by 2023 at which moment the upgrade process for the neutrino facility construction could start.

This document summarises the talks and discussions happened during the VBSCan Mid-Term Scientific Meeting workshop. The VBSCan COST action is dedicated to the coordinated study of vector boson scattering (VBS) from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

The discovery of oscillations and the latest progress in neutrino physics will make possible to observe, for the first time, CP violation in the lepton sector, if it exists. This will help to understand the disappearance of antimatter in the Universe. To go further beyond the current knowledge, it is necessary to develop more and more powerful instruments, but also to combine skills by creating strong international networks between researchers. In this framework, the ESSvSB project proposes to use the proton linac of the European Spallation Source (ESS) currently in construction in Lund (Sweden) to produce a very intense neutrino Super Beam, in parallel with the spallation neutron production. The ESS linac is expected to be fully operational by 2023 delivering 5 MW average power, 2 GeV proton beam, with 2.86 ms long pulses at a rate of 14 Hz. By doubling the pulse rate, an average power of 10 MW can be obtained, providing at the same time 5 MW for the neutron facility and the 5 MW for the production of the neutrino beam. The primary proton beam-line completing the linac will consist of an accumulator ring to compress the beam pulses to 1.3 μs and a switchyard to distribute the protons onto the target station. The secondary beam-line producing neutrinos will consist of a four-horn/target station, a decay tunnel and a beam dump. A megaton scale Water Cherenkov neutrino detector will be located at a baseline of about 500 km in one of the existing mines in Sweden, to measure the neutrino oscillations.

This document summarises the talks and discussions happened during the VBSCan Mid-Term Scientific Meeting workshop. The VBSCan COST action is dedicated to the coordinated study of vector boson scattering (VBS) from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

A systematic search for superfragments (charmed nuclei) has been performed in 22 200 neutrino–emulsion interactions obtained with the CHORUS experiment making use of automatic off-line image analysis. The absence of candidates provides an upper limit for the superfragment production rate of 1.9×10−4 (90% C.L.) relative to neutrino charged-current interactions at an average neutrino energy of 27 GeV. In the same analysis 28 hyperfragment decays were found. For the first time, a production rate of hyperfragments in neutrino–emulsion interactions was obtained. The value of the hyperfragment production rate relative to the neutrino charged-current cross-section was found to be (2.0±0.4(stat)±0.3(syst))×10−3.

The European Spallation Source Neutrino Super Beam (ESSnuSB) project aims at a discovery of leptonic CP violation with a precise measurement of the CP phase angle. ESSnuSB is characterized by an intense neutrino beam to be produced at ESS by a 5-MW proton beam, and the placement of the far detector at the second oscillation maximum. The aims of the near detector for ESSnuSB are neutrino flux and interaction cross section measurements. For this purpose, designs consisting of a fine-grained tracker and a 1-kiloton water Cherenkov detector are under investigation. On the other hand, the far detector will be a water Cherenkov detector with an estimated fiducial volume of 500 kilotons. The design considerations include an evaluation of the stability of the detector hall and excavation sites in deep underground mines. All of the detector simulations are based on frameworks which involve Geant4. A versatile event display toolkit for visualization and physics outreach activities has been developed.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

With the discovery of non-zero value of $\theta_{13}$ mixing angle, the next generation of long-baseline neutrino (LBN) experiments offers the possibility of obtaining statistically significant samples of muon and electron neutrinos and anti-neutrinos with large oscillation effects. In this document we intend to highlight the importance of Near Detector facilities in LBN experiments to both constrain the systematic uncertainties affecting oscillation analyses but also to perform, thanks to their close location, measurements of broad benefit for LBN physics goals. A strong European contribution to these efforts is possible.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

CHORUS Experiment was taking data during the years of 1994–1997. In total about 100 000 charged‐current(CC) neutrino interactions were located in the nuclear emulsion target and fully reconstructed. In addition to the oscillation search, measurements of charm production have been also performed. From the sample of 100 000 events based on the data acquired by new automatic scanning system, 2013 charm‐decay events were selected by a pattern recognition program. A comprehensive study of charm production by neutrinos being made. We report here some of the recent results on charm production and neutrino oscillation results.

We investigate the generalized form of Duffin–Kemmer–Petiau (DKP) equation in the presence of both a position-dependent electrical field and curved spacetime for the 2-dimensional anti-de Sitter spacetime. Moreover, we derive both the asymptotic wave function and construct energy quantization with the help of the properties of gamma function. All thermodynamic quantities of the system have been calculated with the help of the Euler–MacLaurin formula in the final state.