arXiv subjects

V. Matveev

Publications and source records attributed to V. Matveev.

At least 37 records · Page 2Linked to original sources

arXiv2024

$K_S^0$ meson production in inelastic p+p interactions at 31, 40 and 80 GeV/c beam momentum measured by NA61/SHINE at the CERN SPS

Measurements of $K_S^0$ meson production via its $π^{+} π^{-}$ decay mode in inelastic $\textit{p+p}$ interactions at incident projectile momenta of 31, 40 and 80 GeV/$c$ ($\sqrt{s_{NN}}=7.7, 8.8$ and $12.3$ GeV, respectively) are presented. The data were recorded by the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. Double-differential distributions were obtained in transverse momentum and rapidity. The mean multiplicities of $K_S^0$ mesons were determined to be $(5.95 \pm 0.19 (stat) \pm 0.22 (sys)) \times 10^{-2}$ at 31 GeV/$c$, $(7.61 \pm 0.13 (stat) \pm 0.31 (sys)) \times 10^{-2}$ at 40 GeV/$c$ and $(11.58 \pm 0.12 (stat) \pm 0.37 (sys)) \times 10^{-2}$ at 80 GeV/$c$. The results on $K^{0}_{S}$ production are compared with model calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from other experiments.

hep-ex↗

arXiv2024

Search for a critical point of strongly-interacting matter in central $^{40}$Ar +$^{45}$Sc collisions at 13$A$-75$A$ GeV/$c$ beam momentum

The critical point of strongly interacting matter is searched for at the CERN SPS by the NA61/SHINE experiment in central $^{40}$Ar +$^{45}$Sc collisions at 13$A$, 19$A$, 30$A$, 40$A$, and 75$A$ GeV/$c$. The dependence of the second-order scaled factorial moments of proton multiplicity distributions on the number of subdivisions in transverse momentum space is measured. The intermittency analysis uses statistically independent data sets for every subdivision in transverse and cumulative-transverse momentum variables. The results obtained do not indicate the searched intermittent pattern. An upper limit on the fraction of correlated protons and the intermittency index is obtained based on a comparison with the Power-law Model.

nucl-ex↗

arXiv2023

Measurements of $π^+$, $π^-$, $p$, $\bar{p}$, $K^+$ and $K^-$ production in 120 GeV/$c$ p + C interactions

This paper presents multiplicity measurements of charged hadrons produced in 120 GeV/$c$ proton-carbon interactions. The measurements were made using data collected at the NA61/SHINE experiment during two different data-taking periods, with increased phase space coverage in the second configuration due to the addition of new subdetectors. Particle identification via $dE/dx$ was employed to obtain double-differential production multiplicities of $π^+$, $π^-$, $p$, $\bar{p}$, $K^+$ and $K^-$. These measurements are presented as a function of laboratory momentum in intervals of laboratory polar angle covering the range from 0 to 450 mrad. They provide crucial inputs for current and future long-baseline neutrino experiments, where they are used to estimate the initial neutrino flux.

hep-ex↗

arXiv2023

Search for the critical point of strongly-interacting matter in ${}^{40}$Ar + ${}^{45}$Sc collisions at 150A GeV/c using scaled factorial moments of protons

The critical point of dense, strongly interacting matter is searched for at the CERN SPS in ${}^{40}$Ar + ${}^{45}$Sc collisions at 150A GeV/c. The dependence of second-order scaled factorial moments of proton multiplicity distribution on the number of subdivisions of transverse momentum space is measured. The intermittency analysis is performed using both transverse momentum and cumulative transverse momentum. For the first time, statistically independent data sets are used for each subdivision number. The obtained results do not indicate any statistically significant intermittency pattern. An upper limit on the fraction of critical proton pairs and the power of the correlation function is obtained based on a comparison with the Power-law Model developed for this purpose.

nucl-ex↗

arXiv2023

Measurements of $K^0_{\textrm{S}}$, $Λ$ and $\barΛ$ production in 120 GeV/$c$ p + C interactions

This paper presents multiplicity measurements of $K^0_{\textrm{S}}$, $Λ$, and $\barΛ$ produced in 120 GeV/$c$ proton-carbon interactions. The measurements were made using data collected at the NA61/SHINE experiment during two different periods. Decays of these neutral hadrons impact the measured $π^+$, $π^-$, $p$ and $\bar{p}$ multiplicities in the 120 GeV/$c$ proton-carbon reaction, which are crucial inputs for long-baseline neutrino experiment predictions of neutrino beam flux. The double-differential multiplicities presented here will be used to more precisely measure charged-hadron multiplicities in this reaction, and to re-weight neutral hadron production in neutrino beam Monte Carlo simulations.

hep-ex↗

arXiv2023

Updated constraints on sterile neutrino mixing in the OPERA experiment using a new $ν_e$ identification method

This paper describes a new $ν_e$ identification method specifically designed to improve the low-energy ($< 30\,\mathrm{GeV}$) $ν_e$ identification efficiency attained by enlarging the emulsion film scanning volume with the next generation emulsion readout system. A relative increase of 25-70% in the $ν_e$ low-energy region is expected, leading to improvements in the OPERA sensitivity to neutrino oscillations in the framework of the 3 + 1 model. The method is applied to a subset of data where the detection efficiency increase is expected to be more relevant, and one additional $ν_e$ candidate is found. The analysis combined with the $ν_τ$ appearance results improves the upper limit on $\sin^2 2θ_{μe}$ to 0.016 at 90% C.L. in the MiniBooNE allowed region $Δm^2_{41} \sim 0.3\,\mathrm{eV}^2$.

hep-ex↗

arXiv2023

Measurements of $π^\pm$, $K^\pm$, $p$ and $\bar{p}$ spectra in $^7$Be+$^9$Be collisions at beam momenta from 19$A$ to 150$A$ GeV/$c$ with the NA61/SHINE spectrometer at the CERN SPS

The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of $π^\pm$, $K^\pm$, $p$ and $\bar{p}$ produced in the 20$\%$ most $central$ $^7$Be+$^9$Be collisions at beam momenta of 19$A$, 30$A$, 40$A$, 75$A$ and 150$A$ GeV/$c$. The energy dependence of the $K^\pm$/$π^\pm$ ratios as well as of inverse slope parameters of the $K^\pm$ transverse mass distributions are close to those found in inelastic $p$+$p$ reactions. The new results are compared to the world data on $p$+$p$ and Pb+Pb collisions as well as to predictions of the EPOS, UrQMD, AMPT, PHSD and SMASH models.

hep-ex↗

arXiv2022

Measurement of Hadron Production in $π^-$-C Interactions at 158 and 350 GeV/c with NA61/SHINE at the CERN SPS

We present a measurement of the momentum spectra of $π^\pm$, K$^\pm$, p$^\pm$, $Λ$, $\barΛ$ and K$^{0}_{S}$ produced in interactions of negatively charged pions with carbon nuclei at beam momenta of 158 and 350 GeV/c. The total production cross sections are measured as well. The data were collected with the large-acceptance spectrometer of the fixed target experiment NA61/SHINE at the CERN SPS. The obtained double-differential $p$-$p_T$ spectra provide a unique reference data set with unprecedented precision and large phase-space coverage to tune models used for the simulation of particle production in extensive air showers in which pions are the most numerous projectiles.

nucl-ex↗

arXiv2022

$K^{*}(892)^0$ meson production in inelastic $p+p$ interactions at 40 and 80 GeV/$c$ beam momenta measured by NA61/SHINE at the CERN SPS

Measurements of $K^{*}(892)^0$ resonance production via its $K^{+}π^{-}$ decay mode in inelastic $p+p$ collisions at beam momenta 40 and 80 GeV/$c$ ($\sqrt{s_{NN}}=8.8$ and 12.3 GeV) are presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The \textit{template} method was used to extract the $K^{*}(892)^0$ signal. Transverse momentum and rapidity spectra were obtained. The mean multiplicities of $K^{*}(892)^0$ mesons were found to be $(35.1 \pm 1.3 \mathrm{(stat)} \pm 3.6 \mathrm{(sys)) \cdot 10^{-3}}$ at 40 GeV/$c$ and $(58.3 \pm 1.9 \mathrm{(stat)} \pm 4.9 \mathrm{(sys)) \cdot 10^{-3}}$ at 80 GeV/$c$. The NA61/SHINE results are compared with the EPOS1.99 and Hadron Resonance Gas models as well as with world data. The transverse mass spectra of $K^{*}(892)^0$ mesons and other particles previously reported by NA61/SHINE were fitted within the Blast-Wave model. The transverse flow velocities are close to 0.1--0.2 of the speed of light and are significantly smaller than the ones determined in heavy nucleus-nucleus interactions at the same beam momenta.

nucl-ex↗

arXiv2022

Search for photoproduction of axion-like particles at GlueX

We present a search for axion-like particles, $a$, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the $a$-gluon coupling is dominant. The search uses $a\toγγ$ and $a\toπ^+π^-π^0$ decays, and a data sample corresponding to an integrated luminosity of 168 pb$^{-1}$ collected with the GlueX detector. The search for $a\toγγ$ decays is performed in the mass range of $180 < m_a < 480$ MeV, while the search for $a\toπ^+π^-π^0$ decays explores the $600 < m_a < 720$ MeV region. No evidence for a signal is found, and 90% confidence-level exclusion limits are placed on the $a$-gluon coupling strength. These constraints are the most stringent to date over much of the mass ranges considered.

hep-ex↗

arXiv2022

A cryogenic tracking detector for antihydrogen detection in the AEgIS experiment

We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1 T superconducting magnet of the AEgIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4 K and are read out by silicon photomultipliers (MPPCs) at near room temperature. FACT provides the antiproton/antihydrogen annihilation position information with a few ns timing resolution. We present the hardware and software developments which led to the successful operation of the detector for antihydrogen detection and the results of an antiproton-loss based efficiency assessment. The main background to the antihydrogen signal is that of the positrons impinging onto the positronium conversion target and creating a large amount of gamma rays which produce a sizeable signal in the MPPCs shortly before the antihydrogen signal is expected. We detail the characterization of this background signal and its impact on the antihydrogen detection efficiency.

physics.ins-det↗

arXiv2022

Measurement of Spin Density Matrix Elements in $Λ(1520)$ Photoproduction at 8.2-8.8 GeV

We report on the measurement of spin density matrix elements of the $Λ(1520)$ in the photoproduction reaction $γp\rightarrow Λ(1520)K^+$, via its subsequent decay to $K^{-}p$. The measurement was performed as part of the GlueX experimental program in Hall D at Jefferson Lab using a linearly polarized photon beam with $E_γ=$ 8.2-8.8 GeV. These are the first such measurements in this photon energy range. Results are presented in bins of momentum transfer squared, $-(t-t_\text{0})$. We compare the results with a Reggeon exchange model and determine that natural exchange amplitudes are dominant in $Λ(1520)$ photoproduction.

nucl-ex↗

arXiv2022

Rydberg-positronium velocity and self-ionization studies in 1T magnetic field and cryogenic environment

We characterized the pulsed Rydberg-positronium production inside the AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) apparatus in view of antihydrogen formation by means of a charge exchange reaction between cold antiprotons and slow Rydberg-positronium atoms. Velocity measurements on positronium along two axes in a cryogenic environment (10K) and in 1T magnetic field were performed. The velocimetry was done by MCP-imaging of photoionized positronium previously excited to the $n=3$ state. One direction of velocity was measured via Doppler-scan of this $n=3$-line, another direction perpendicular to the former by delaying the exciting laser pulses in a time-of-flight measurement. Self-ionization in the magnetic field due to motional Stark effect was also quantified by using the same MCP-imaging technique for Rydberg positronium with an effective principal quantum number $n_{eff}$ ranging between 14 and 22. We conclude with a discussion about the optimization of our experimental parameters for creating Rydberg-positronium in preparation for an efficient pulsed production of antihydrogen.

physics.atom-ph↗

arXiv2022

$K^{0}_{S}$ meson production in inelastic $\textit{p+p}$ interactions at 158 GeV/c beam momentum measured by NA61/SHINE at the CERN SPS

The production of $K^{0}_{S}$ mesons in inelastic $\textit{p+p}$ collisions at beam momentum 158 GeV/c ($\sqrt{s_{NN}}=17.3$ GeV) was measured with the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. Double-differential distributions were obtained in transverse momentum and rapidity. The mean multiplicity of $K^{0}_{S}$ was determined to be $0.162 \pm 0.001 (stat.) \pm 0.011 (sys.)$. The results on $K^{0}_{S}$ production are compared with model predictions (EPOS 1.99, SMASH 2.0, PHSD and UrQMD 3.4 models) as well as with published world data.

hep-ex↗

arXiv2022

Measurements of $Ξ^{-}$ and $\overlineΞ^{+}$ production in proton-proton interactions at $\sqrt{s_{NN}}$ = 17.3 GeV in the NA61/SHINE experiment

The production of $Ξ(1321)^{-}$ and $\overlineΞ(1321)^{+}$ hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam momentum of 158 GeV/textit{c}. Double differential distributions in rapidity y and transverse momentum $p_{T}$ are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both $Ξ^{-}$ and $\overlineΞ^{+}$. The rapidity and transverse momentum spectra are compared to transport model predictions. The $Ξ^{-}$ mean multiplicity in inelastic p+p interactions at 158~\GeVc is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair.

nucl-ex↗

arXiv2021

Improved exclusion limit for light dark matter from $e^+e^-$ annihilation in NA64

The current most stringent constraints for the existence of sub-GeV dark matter coupling to Standard Model via a massive vector boson $A^\prime$ were set by the NA64 experiment for the mass region $m_{A^\prime}\lesssim 250$ MeV, by analyzing data from the interaction of $2.84\cdot10^{11}$ 100-GeV electrons with an active thick target and searching for missing-energy events. In this work, by including $A^\prime$ production via secondary positron annihilation with atomic electrons, we extend these limits in the $200$-$300$ MeV region by almost an order of magnitude, touching for the first time the dark matter relic density constrained parameter combinations. Our new results demonstrate the power of the resonant annihilation process in missing energy dark-matter searches, paving the road to future dedicated $e^+$ beam efforts.

hep-ex↗

arXiv2021

Measurements of $Ξ\left(1530\right)^{0}$ and $\overlineΞ\left(1530\right)^{0}$ production in proton-proton interactions at $\sqrt{s_{NN}}$ = 17.3 GeV in the NA61/SHINE experiment

Double-differential yields of $Ξ\left(1530\right)^{0}$ and $\overlineΞ\left(1530\right)^{0}$ resonances produced in \pp interactions were measured at a laboratory beam momentum of 158~\GeVc. This measurement is the first of its kind in \pp interactions below LHC energies. It was performed at the CERN SPS by the \NASixtyOne collaboration. Double-differential distributions in rapidity and transverse momentum were obtained from a sample of 26$\cdot$10$^6$ inelastic events. The spectra are extrapolated to full phase space resulting in mean multiplicity of $Ξ\left(1530\right)^{0}$ (6.73 $\pm$ 0.25 $\pm$ 0.67)$\times10^{-4}$ and $\overlineΞ\left(1530\right)^{0}$ (2.71 $\pm$ 0.18 $\pm$ 0.18)$\times10^{-4}$. The rapidity and transverse momentum spectra and mean multiplicities were compared to predictions of string-hadronic and statistical model calculations.

nucl-ex↗

arXiv2021

Measurements of multiplicity fluctuations of identified hadrons in inelastic proton-proton interactions at the CERN Super Proton Synchrotron

Measurements of multiplicity fluctuations of identified hadrons produced in inelastic p+p interactions at 31, 40, 80, and 158~\GeVc beam momentum are presented. Three different measures of multiplicity fluctuations are used: the scaled variance $ω$ and strongly intensive measures $Σ$ and $Δ$. These fluctuation measures involve second and first moments of joint multiplicity distributions. Data analysis is performed using the Identity method which corrects for incomplete particle identification. Strongly intensive quantities are calculated in order to allow for a direct comparison to corresponding results on nucleus-nucleus collisions. The results for different hadron types are shown as a function of collision energy. A comparison with predictions of string-resonance Monte-Carlo models: Epos, Smash and Venus, is also presented.

nucl-ex↗