Open charm measurements with the NA61/SHINE experiment at the CERN SPS

The strong interactions programme of the NA61/SHINE experiment at the CERN SPS has been extended through the use of new silicon Vertex Detector, which allows for reconstructing open charm particles. The detector was designed to identify those particles by means of a precise reconstruction of their primary and secondary vertices. An initial version of the Vertex Detector, called SAVD (Small Acceptance Vertex Detector), was installed end of 2016. It was operated in a Pb+Pb calibration beam time in 2016, and with Xe+La in 2017. A further Pb+Pb beam time is scheduled for late 2018. The first indications of a D$^0$ peak were observed in the data obtained from the 2016 Pb+Pb run. This work introduces the physics motivation behind the open charm measurements, and the status of the analysis of the collected data on open charm production. Moreover, the plans of future open charm measurements in NA61/SHINE experiment and the related to upgrades of the vertex detector will be discussed.Comment: XIII International Conference on Beauty, Charm and Hyperon Hadrons (BEACH 2018), Lisbon, Portuga

Open Charm measurements at the NA61 experiment at CERN SPS

The strong interactions programme of the NA61/SHINE experiment at CERN SPS has been extended through the use of new silicon Vertex Detector which provides precise measurements of exotic particles with short lifetime. The detector was designed to meet the challenges of primary and secondary vertexes reconstruction at high spatial resolution. An initial version of the Vertex Detector called SAVD (Small Acceptance Vertex Detector) was installed last end of 2016, and data was from Pb+Pb collisions was collected in 2016, for Xe+La in 2017, as well as further Pb+Pb collisions this year. First indication of a D$^0$ peak at SPS energies has been observed. The physics motivation behind the open charm measurements will be discussed, as well as the analysis of collected data on open charm production and the future plans of open charm measurements in NA61/SHINE experiment related to the upgraded version of the vertex detector.Comment: XXth International Seminar on High Energy Physics (Quarks 2018), Valday, Russia. arXiv admin note: text overlap with arXiv:1810.00637, arXiv:1810.0275

Open charm measurements at CERN SPS energies with the new vertex detector of the NA61/SHINE experiment : status and plans

The study of open charm meson production provides an efficient tool for detailed investigations of the properties of hot and dense matter formed in nucleus-nucleus collisions. The interpretation of the existing data from the CERN Super Proton Synchrotron (SPS) suffers from a lack of knowledge about the total charm production rate. To overcome this limitation, the heavy-ion program of the NA61/SHINE experiment at the CERN SPS has been upgraded to allow for precise measurements of particles with a short lifetime. A new vertex detector (Small Acceptance version of the Vertex Detector (SAVD)) was constructed to meet the challenges of open charm measurements in nucleus-nucleus collisions. The first exploratory data taking of Pb + Pb collisions at 150A GeV/$c$ with the SAVD was performed in 2016, and a $D^0$ signal was extracted in its $D^0 \rightarrow \pi^+ + K^−$ decay channel. This was the first, direct observation of open charm in nucleus-nucleus collisions at the SPS energies. Furthermore, the future plans of open charm measurements in the NA61/SHINE experiment related to the upgraded version of the Vertex Detector are discussed

Open charm measurements in NA61/SHINE at CERN SPS

The measurements of open charm production was proposed as an important tool to investigate the properties of the hot and dense matter formed in nucleus-nucleus collisions as well as to provide the means for model independent interpretation of the existing data on J/ψ suppression. Recently, the experimental setup of the NA61/SHINE experiment was supplemented with a Vertex Detector which was motivated by the importance and the possibility of the first direct measurements of open charm meson production in heavy ion collisions at SPS energies. First test data taken in December 2016 on Pb+Pb collisions at 150A GeV/c allowed to validate the general concept of D0 meson detection via its D0 → π+ + K− decay channel and delivered a first indication of open charm production. The physics motivation of open charm measurements at SPS energies, pilot results on open charm production, and finally, the future plans of open charm measurements in the NA61/SHINE experiment after LS2 are presented

Two-particle correlations in azimuthal angle and pseudorapidity in inelastic p + p interactions at the CERN Super Proton Synchrotron

Results on two-particle ΔηΔϕ correlations in inelastic p + p interactions at 20, 31, 40, 80, and 158 GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the Epos and UrQMD models.ISSN:1434-6044ISSN:1434-605

Track reconstruction in the inhomogeneous magnetic field for Vertex Detector of NA61/SHINE experiment at CERN SPS

The heavy-ion programme of the NA61/SHINE experiment at CERN SPS is expanding to allow precise measurements of exotic particles with lifetime few hundred microns. A Vertex Detector for open charm measurements at the SPS is being constructed by the NA61/SHINE Collaboration to meet the challenges of high spatial resolution of secondary vertices and efficiency of track registration. This task is solved by the application of the coordinate sensitive CMOS Monolithic Active Pixel Sensors with extremely low material budget in the new Vertex Detector. A small-acceptance version of the Vertex Detector is being tested this year, later it will be expanded to a large-acceptance version. Simulation studies will be presented. A method of track reconstruction in the inhomogeneous magnetic field for the Vertex Detector was developed and implemented. Numerical calculations show the possibility of high precision measurements in heavy ion collisions of strange and multi strange particles, as well as heavy flavours, like charmed particles

Open charm measurements at the NA61/SHINE experiment at CERN SPS with the new Vertex Detector

The study of open charm meson production provides an efficient tool for detailed investigations of the properties of hot and dense matter formed in relativistic nucleus-nucleus collisions. In particular, charm mesons are of vivid interest in the context of the phase-transition between confined hadronic matter and the quark-gluon plasma as well as for interpretation of data on J/$\psi$ production measured by the NA38/NA50 and NA60 experiments. Also, such study gives a unique opportunity to test the validity of theoretical models based on perturbative Quantum Chromodynamics and Statistical model approaches for nucleus collisions at the top SPS energy. Such models provide predictions for charm yields, that differ by up to two orders of magnitude. Direct measurements of open charm mesons are challenging since the yields of $D$ mesons are very low and their lifetimes are short, which means that such measurements require precise determination of particle tracks and high primary and secondary vertex resolution. To meet these challenges a new high resolution Small Acceptance Vertex Detector (SAVD) based on silicon pixel sensors MIMOSA-26AHR was constructed and installed in the NA61/SHINE experiment which was motivated by the importance and the possibility of the first direct measurements of open charm mesons in heavy ion collisions at SPS energies. The SAVD was installed in 2016 to perform a test for Pb+Pb reactions with the beam momentum of 150$A$ GeV/$c$. Later, in 2017 and 2018 large statistic data sets have been taken for Xe+La and Pb+Pb collisions at 150$A$ GeV/$c$. Within this PhD project reconstruction and analysis of the collected data of Xe+La and Pb+Pb collisions in the NA61/SHINE experiment were performed in order to determine the yield of $D^0 + \overline{D^0}$. The obtained $D^0 + \overline{D^0}$ signal was the first, direct observation of open charm in nucleus-nucleus collisions at the SPS energies. These results were compared to the theoretical model predictions as well as the estimation made by the NA50/NA60 experiments. Furthermore, the NA61/SHINE experiment plans a systematic measurements of open charm production in Pb+Pb collisions in the period 2021-2024 after the major detector upgrade conducted during the Long Shutdown 2. The performed simulation study of the upgraded Vertex Detector showed, that these future data will allow for the more detailed research of charm particles

Open charm measurements at CERN SPS energies in the NA61/SHINE experiment - status and plans

The study of open charm meson production provides an efficient tool for detailed investigations of the properties of hot and dense matter formed in nucleus-nucleus collisions. In particular, charm mesons are of vivid interest in the context of the phase-transition between confined hadronic matter and the quark-gluon plasma. Recently, the experimental setup of NA61/SHINE experiment was supplemented with a small-acceptance version of the Vertex Detector (SAVD) which was motivated by the importance and the possibility of the first direct measurements of open charm mesons in heavy ion collisions at SPS energies. First exploratory data taking of Pb+Pb collisions at 150$A$ GeV/c with SAVD was performed in 2016, and a $D^0$ signal was extracted in it's $D^0 \rightarrow \pi^{+} + K^{-}$ decay channel. This was the first, direct observation of open charm in nucleus-nucleus collisions at the SPS energies. In 2017 and 2018 a large statistic data set has been taken for Xe+La and Pb+Pb with SAVD at 150$A$ GeV/c; these data are currently under intense analysis.Furthermore, the future plans of open charm measurements in the NA61/SHINE experiment related to the upgraded version of the Vertex Detector are discussed

Open Charm measurements at the NA61 experiment at CERN SPS

The strong interactions programme of the NA61/SHINE experiment at CERN SPS has been extended through the use of new silicon Vertex Detector which provides precise measurements of exotic particles with short lifetime. The detector was designed to meet the challenges of primary and secondary vertexes reconstruction at high spatial resolution. An initial version of the Vertex Detector called SAVD (Small Acceptance Vertex Detector) was installed last end of 2016, and data was from Pb+Pb collisions was collected in 2016, for Xe+La in 2017, as well as further Pb+Pb collisions this year. First indication of a D0 peak at SPS energies has been observed. The physics motivation behind the open charm measurements will be discussed, as well as the analysis of collected data on open charm production and the future plans of open charm measurements in NA61/SHINE experiment related to the upgraded version of the vertex detector