Most search experiments sensitive to quantum chromodynamics (QCD) axion dark matter benefit from microwave cavities, as electromagnetic resonators, that enhance the detectable axion signal power and thus the experimental sensitivity drastically. As the possible axion mass spans multiple orders of magnitude, microwave cavities must be tunable and it is desirable for the cavity to have a tunable frequency range that is as wide as possible. Since the tunable frequency range generally increases as the dimension of the conductor tuning rod increases for a given cylindrical conductor cavity system, we developed a cavity system with a large dimensional tuning rod in order to increase this. We, for the first time, employed not only a piezoelectric motor, but also gears to drive a large and accordingly heavy tuning rod, where such a combination to increase driving power can be adopted for extreme environments as is the case for axion dark matter experiments: cryogenic, high-magnetic-field, and high vacuum. Thanks to such higher power derived from the piezoelectric motor and gear combination, we realized a wideband tunable cavity whose frequency range is about 42% of the central resonant frequency of the cavity, without sacrificing the experimental sensitivity too much.

The production cross section of inclusive J/$\psi$ pairs in pp collisions at a centre-of-mass energy $\sqrt{s} = 13$ TeV is measured with ALICE. The measurement is performed for J/$\psi$ in the rapidity interval $2.50$. The production cross section of inclusive J/$\psi$ pairs is reported to be $10.3 \pm 2.3 {\rm (stat.)} \pm 1.3 {\rm (syst.)}$ nb in this kinematic interval. The contribution from non-prompt J/$\psi$ (i.e. originated from beauty-hadron decays) to the inclusive sample is evaluated. The effective double-parton scattering cross section is computed, neglecting the single-parton scattering contribution.

Abstract The signal to noise ratio efficiency ϵ SNR in axion dark matter searches has been estimated using large-statistic simulation data reflecting the background information and the expected axion signal power obtained from a real experiment. This usually requires a lot of computing time even with the assistance of powerful computing resources. Employing a Savitzky-Golay filter for background subtraction, in this work, we estimated a fully analytical ϵ SNR without relying on large-statistic simulation data, but only with an arbitrary axion mass and the relevant signal shape information. Hence, our work can provide ϵ SNR using minimal computing time and resources prior to the acquisition of experimental data, without the detailed information that has to be obtained from real experiments. Axion haloscope searches have been observing the coincidence that the frequency independent scale factor ξ is approximately consistent with the ϵ SNR. This was confirmed analytically in this work, when the window length of the Savitzky-Golay filter is reasonably wide enough, i.e., at least 5 times the signal window.

A newly developed observable for correlations between symmetry planes, which characterize the direction of the anisotropic emission of produced particles, is measured in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV with ALICE. This so-called Gaussian Estimator allows for the first time the study of these quantities without the influence of correlations between different flow amplitudes. The centrality dependence of various correlations between two, three and four symmetry planes is presented. The ordering of magnitude between these symmetry plane correlations is discussed and the results of the Gaussian Estimator are compared with measurements of previously used estimators. The results utilizing the new estimator lead to significantly smaller correlations than reported by studies using the Scalar Product method. Furthermore, the obtained symmetry plane correlations are compared to state-of-the-art hydrodynamic model calculations for the evolution of heavy-ion collisions. While the model predictions provide a qualitative description of the data, quantitative agreement is not always observed, particularly for correlators with significant non-linear response of the medium to initial state anisotropies of the collision system. As these results provide unique and independent information, their usage in future Bayesian analysis can further constrain our knowledge on the properties of the QCD matter produced in ultrarelativistic heavy-ion collisions.

The production of prompt $\rm \Lambda_{\rm c}^{+}$ baryons at midrapidity ($|y|<0.5$) was measured in central (0-10%) and mid-central (30-50%) Pb-Pb collisions at the center-of-mass energy per nucleon-nucleon pair $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE detector. The $\rm \Lambda_{\rm c}^{+}$ production yield, the $\rm \Lambda_{\rm c}^{+}$/D$^0$ production ratio, and the $\rm \Lambda_{\rm c}^{+}$ nuclear modification factor $R_{\rm AA}$ are reported. The results are more precise and more differential in transverse momentum ($p_{\rm T}$) and centrality with respect to previous measurements. The $\rm \Lambda_{\rm c}^{+}$/D$^0$ ratio, which is enhanced with respect to the pp measurement for $4< p_{\rm T} < 8$ GeV/$c$, is described by theoretical calculations that model the charm-quark transport in the quark-gluon plasma and include hadronization via both coalescence and fragmentation mechanisms.

The first measurements of skewness and kurtosis of mean transverse momentum ($\langle p_\mathrm{T}\rangle$) fluctuations are reported in Pb$-$Pb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV, Xe$-$Xe collisions at $\sqrt{s_\mathrm{NN}}$ $=$ 5.44 TeV and pp collisions at $\sqrt{s} = 5.02$ TeV using the ALICE detector. The measurements are carried out as a function of system size $\langle \mathrm{d}N_\mathrm{ch}/\mathrm{d}\eta\rangle_{|\eta|<0.5}^{1/3}$, using charged particles with transverse momentum ($p_\mathrm{T}$) and pseudorapidity ($\eta$), in the range $0.2 < p_\mathrm{T} < 3.0$ GeV/$c$ and $|\eta| < 0.8$, respectively. In Pb$-$Pb and Xe$-$Xe collisions, positive skewness is observed in the fluctuations of $\langle p_\mathrm{T}\rangle$ for all centralities, which is significantly larger than what would be expected in the scenario of independent particle emission. This positive skewness is considered a crucial consequence of the hydrodynamic evolution of the hot and dense nuclear matter created in heavy-ion collisions. Furthermore, similar observations of positive skewness for minimum bias pp collisions are also reported here. Kurtosis of $\langle p_\mathrm{T}\rangle$ fluctuations is found to be in good agreement with the kurtosis of Gaussian distribution, for most central Pb$-$Pb collisions. Hydrodynamic model calculations with MUSIC using Monte Carlo Glauber initial conditions are able to explain the measurements of both skewness and kurtosis qualitatively from semicentral to central collisions in Pb--Pb system. Color reconnection mechanism in PYTHIA8 model seems to play a pivotal role in capturing the qualitative behavior of the same measurements in pp collisions.

Antimatter particles such as positrons and antiprotons abound in the cosmos. Much less common are light antinuclei, composed of antiprotons and antineutrons, which can be produced in our galaxy via high-energy cosmic-ray collisions with the interstellar medium or could also originate from the annihilation of the still undiscovered dark-matter particles. On Earth, the only way to produce and study antinuclei with high precision is to create them at high-energy particle accelerators like the Large Hadron Collider (LHC). Though the properties of elementary antiparticles have been studied in detail, knowledge of the interaction of light antinuclei with matter is rather limited. This work focuses on the determination of the disappearance probability of \ahe\ when it encounters matter particles and annihilates or disintegrates. The material of the ALICE detector at the LHC serves as a target to extract the inelastic cross section for \ahe\ in the momentum range of $1.17 \leq p < 10$ GeV/$c$. This inelastic cross section is measured for the first time and is used as an essential input to calculations of the transparency of our galaxy to the propagation of $^{3}\overline{\rm He}$ stemming from dark-matter decays and cosmic-ray interactions within the interstellar medium. A transparency of about 50% is estimated using the GALPROP program for a specific dark-matter profile and a standard set of propagation parameters. For cosmic-ray sources, the obtained transparency with the same propagation scheme varies with increasing $^{3}\overline{\rm He}$ momentum from 25% to 90%. The absolute uncertainties associated to the $^{3}\overline{\rm He}$ inelastic cross section measurements are of the order of 10%$-$15%. The reported results indicate that $^{3}\overline{\rm He}$ nuclei can travel long distances in the galaxy, and can be used to study cosmic-ray interactions and dark-matter decays.

A fast data acquisition (DAQ) system for axion dark matter searches utilizing a microwave resonant cavity, also known as axion haloscope searches, has been developed with a two-channel digitizer that can sample 16-bit amplitudes at rates up to 180 MSamples/s. First, we realized a practical DAQ efficiency of greater than 99% for a single DAQ channel, where the DAQ process includes the online fast Fourier transforms (FFTs). Using an IQ mixer and two parallel DAQ channels, we then also implemented a software-based image rejection without losing the DAQ efficiency. This work extends our continuing effort to improve the figure of merit in axion haloscope searches, the scanning rate.

Korea Institute of Science and Technology Information (KISTI) is a Worldwide LHC Computing Grid (WLCG) Tier-1 center mandated to preserve raw data produced from A Large Ion Collider Experiment (ALICE) experiment using the world’s largest particle accelerator, the Large Hadron Collider (LHC) at European Organization for Nuclear Research (CERN). Physical medium used widely for long-term data preservation is tape, thanks to its reliability and least price per capacity compared to other media such as optical disk, hard disk, and solid-state disk. However, decreasing numbers of manufacturers for both tape drives and cartridges, and patent disputes among them escalated risk of market. As alternative to tape-based data preservation strategy, we proposed disk-only erasure-coded archival storage system, Custodial Disk Storage (CDS), powered by Exascale Open Storage (EOS), an open-source storage management software developed by CERN. CDS system consists of 18 high density Just-Bunch-Of-Disks (JBOD) enclosures attached to 9 servers through 12 Gbps Serial Attached SCSI (SAS) Host Bus Adapter (HBA) interfaces via multiple paths for redundancy and multiplexing. For data protection, we introduced Reed-Solomon (RS) (16, 4) Erasure Coding (EC) layout, where the number of data and parity blocks are 12 and 4 respectively, which gives the annual data loss probability equivalent to 5×10-14. In this paper, we discuss CDS system design based on JBOD products, performance limitations, and data protection strategy accommodating EOS EC implementation. We present CDS operations for ALICE experiment and long-term power consumption measurement.

The p_{T}-differential production cross sections of prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) charmed hadrons are measured at midrapidity (|y|<0.5) in pp collisions at sqrt[s]=13 TeV. This is the first measurement of Σ_{c}^{0,++} production in hadronic collisions. Assuming the same production yield for the three Σ_{c}^{0,+,++} isospin states, the baryon-to-meson cross section ratios Σ_{c}^{0,+,++}/D^{0} and Λ_{c}^{+}/D^{0} are calculated in the transverse momentum (p_{T}) intervals 2

Data are important and ever growing in data-intensive scientific environments. Such research data growth requires data storage systems that play pivotal roles in data management and analysis for scientific discoveries. Redundant Array of Independent Disks (RAID), a well-known storage technology combining multiple disks into a single large logical volume, has been widely used for the purpose of data redundancy and performance improvement. However, this requires RAID-capable hardware or software to build up a RAID-enabled disk array. In addition, it is difficult to scale up the RAID-based storage. In order to mitigate such a problem, many distributed file systems have been developed and are being actively used in various environments, especially in data-intensive computing facilities, where a tremendous amount of data have to be handled. In this study, we investigated and benchmarked various distributed file systems, such as Ceph, GlusterFS, Lustre and EOS for data-intensive environments. In our experiment, we configured the distributed file systems under a Reliable Array of Independent Nodes (RAIN) structure and a Filesystem in Userspace (FUSE) environment. Our results identify the characteristics of each file system that affect the read and write performance depending on the features of data, which have to be considered in data-intensive computing environments.

The production of $\Lambda$ baryons and ${\rm K}^{0}_{\rm S}$ mesons (${\rm V}^{0}$ particles) was measured in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5$ TeV and pp collisions at $\sqrt{s} = 7$ TeV with ALICE at the LHC. The production of these strange particles is studied separately for particles associated with hard scatterings and the underlying event to shed light on the baryon-to-meson ratio enhancement observed at intermediate transverse momentum ($p_{\rm T}$) in high multiplicity pp and p-Pb collisions. Hard scatterings are selected on an event-by-event basis with jets reconstructed with the anti-$k_{\rm T}$ algorithm using charged particles. The production of strange particles associated with jets $p_{\rm T,\;jet}^{\rm ch}>10$ GeV/$c$ is reported as a function of $p_{\rm T}$ in both systems; and its dependence on $p_{\rm T}$ with jets $p_{\rm T,\;jet}^{\rm ch}>20$ GeV/$c$ and on angular distance from the jet axis, $R({\rm V}^{0},\;{\rm jet})$, for jets with $p_{\rm T,\;jet}^{\rm ch} > 10$ GeV/$c$ are reported in p-Pb collisions. The results are compared with the strange particle production in the underlying event. The $\Lambda/{\rm K}^{0}_{\rm S}$ ratio associated with jets in p-Pb collisions for $R({\rm V}^{0},\;{\rm jet})<0.4$ is consistent with the ratio measured in pp collisions and with the expectation of jets fragmenting in vacuum given by the PYTHIA event generator.

A real-time Data Acquisition (DAQ) system for the CULTASK axion haloscope experiment was constructed and tested. The CULTASK is an experiment to search for cosmic axions using resonant cavities, to detect photons from axion conversion through the inverse Primakoff effect in a few GHz frequency range in a very high magnetic field and at an ultra low temperature. The constructed DAQ system utilizes a Field Programmable Gate Array (FPGA) for data processing and Fast Fourier Transformation. This design along with a custom Ethernet packet designed for real-time data transfer enables 100% DAQ efficiency, which is the key feature compared with a commercial spectrum analyzer. This DAQ system is optimally designed for RF signal detection in the axion experiment, with 100 Hz frequency resolution and 500 kHz analysis window. The noise level of the DAQ system averaged over 100,000 measurements is around-111.7 dBm. From a pseudo-data analysis, an improvement of the signal-to-noise ratio due to repeating and averaging the measurements using this real-time DAQ system was confirmed.

Femtoscopic correlations with the particle pair combinations K$^0_{\rm S}$K$^0_{\rm S}$ and K$^0_{\rm S}$K$^\pm$ are studied in pp collisions at $\sqrt{s}=5.02$ and $13$ TeV by the ALICE experiment. At both energies, boson source parameters are extracted for both pair combinations, by fitting models based on Gaussian size distributions of the sources, to the measured two-particle correlation functions. The interaction model used for the K$^0_{\rm S}$K$^0_{\rm S}$ analysis includes quantum statistics and strong final-state interactions through the $f_0(980)$ and $a_0(980)$ resonances. The model used for the K$^0_{\rm S}$K$^\pm$ analysis includes only the final-state interaction through the $a_0$ resonance. Source parameters extracted in the present work are compared with published values from pp collisions at $\sqrt{s}=$ 7 TeV and the different pair combinations are found to be consistent. From the finding that the strength of the K$^0_{\rm S}$K$^0_{\rm S}$ correlations is significantly greater than the strength of the K$^0_{\rm S}$K$^\pm$ correlations, the new results are compatible with the $a_0$ resonance being a tetraquark state of the form $(q_1,\overline{q_2}, s, \overline{s})$, where $q_1$ and $q_2$ are $u$ or $d$ quarks.

A fast data acquisition (DAQ) system for axion dark matter searches utilizing a microwave resonant cavity, also known as axion haloscope searches, has been developed with a two-channel digitizer that can sample 16-bit amplitudes at rates up to 180 MSamples/s. First, we realized a practical DAQ efficiency of about 100% for a single DAQ channel, where the DAQ includes the online fast Fourier transforms (FFTs). Using an IQ mixer and two parallel DAQ channels, we then also implemented a software-based image rejection without losing DAQ efficiency. This work extends our continuing effort to improve the figure of merit in axion haloscope searches, the scanning rate.

CAPP-8TB is an axion dark matter search experiment dedicated to an axion mass search near 6.7 μeV. The experiment uses a microwave resonant cavity under a strong magnetic field of 8 T produced by a superconducting solenoid magnet in a dilution refrigerator. We describe the experimental configuration used to search for a mass range of 6.62 to 6.82 μeV in the first phase of the experiment. We also discuss the next phase of the experiment and its prospects.