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Equivalence between classical and quantum dynamics. Neutral kaons and electric circuits

An equivalence between the Schroedinger dynamics of a quantum system with a finite number of basis states and a classical dynamics is presented. The equivalence is an isomorphism that connects in univocal way both dynamical systems. We treat the particular case of neutral kaons and found a class of electric networks uniquely related to the kaon system finding the complete map between the matrix elements of the effective Hamiltonian of kaons and those elements of the classical dynamics of the networks. As a consequence, the relevant {epsilon} parameter that measures CP violation in the kaon system is completely determined in terms of network parameters. - Highlights: > We provide a formal equivalence between classical and quantum dynamics. > We make use of the decomplexification concept. > Neutral kaon systems can be represented by electric circuits. > CP symmetry violation can be taken into account by non-reciprocity. > Non-reciprocity is represented by gyrators.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

The kaon identification system in the NA62 experiment at CERN

The main goal of the NA62 experiment at CERN is to measure the branching ratio of the ultra-rare K{sup +} → π{sup +} ν ν-bar decay with 10% accuracy. NA62 will use a 750 MHz high-energy un-separated charged hadron beam, with kaons corresponding to ∼6% of the beam, and a kaon decay-in-flight technique. The positive identification of kaons is performed with a differential Cherenkov detector (CEDAR), filled with Nitrogen gas and placed in the incoming beam. To stand the kaon rate (45 MHz average) and meet the performances required in NA62, the Cherenkov detector has been upgraded (KTAG) with new photon detectors, readout, mechanics and cooling systems. The KTAG provides a fast identification of kaons with an efficiency of at least 95% and precise time information with a resolution below 100 ps. A half-equipped KTAG detector has been commissioned during a technical run at CERN in 2012, while the fully equipped detector, its readout and front-end have been commissioned during a pilot run at CERN in October 2014. The measured time resolution and efficiency are within the required performances. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

First simultaneous global QCD analysis of kaon and pion parton distributions with lattice QCD constraints

We perform the first simultaneous global QCD analysis of pion and kaon parton distribution functions (PDFs) constrained by pion- and kaon-induced Drell-Yan (DY) and leading neutron electroproduction data together with lattice QCD data on pion and kaon PDF moments. The analysis indicates a softer valence u ¯ distribution in the K − than in the π − and a significantly more peaked valence s -quark density in K − compared with the u ¯ . The effective exponent governing the high- x behavior of the PDF is found to be larger for u ¯ in the kaon, β u ¯ K − = 1.6 ( 2 ) , than in the pion, β u ¯ π − = 1.16 ( 4 ) , in the range 0.7 ≤ x ≤ 0.95 . From the gluon momentum fractions, we find the pion’s gluon content accounts for ≈ 1 / 3 of the mass budget of the pion at μ = 2 GeV , but only ≈ 1 / 4 for the kaon.

Barry, P. C. [Argonne National Laboratory] (ORCID:↗

Exploring Hadron Structure Through Exclusive Kaon Electroproduction

The kaon electroproduction cross section was extracted from data from the E93-018 and the E01-004 (FPI-2) experiments taken at the Thomas Jefferson National Accelerator Facility in the p(e,e'K + )Λ channel. The cross section was fully separated into longitudinal, transverse, and two interference components at four-momentum transfers Q 2 of 1.0 (GeV/c) 2 (with center of mass energy W=1.81 GeV), 1.36 and 2.07 (GeV/c) 2 (W=2.31 GeV). The kaon form factor (FK) was extracted from the longitudinal cross section in these kinematics using the Regge model by Vanderhaeghen, Guidal, and Laget. Results show F K to be systematically lower than the empirical monopole form, although still compatible with this form within the estimated uncertainties. The resulting kaon form factor values were combined with the world pion and kaon form factor data to extract the transverse change densities of the pion and kaon. These were compared to that of the proton, showing a possible experimental glimpse of the transition between the proton core and the meson cloud in terms of transverse densities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Measurement of the Kaon Production Normalization in the NuMI Target Using Uncontained Charged-Current Muon Neutrino Interactions in the NOvA Far Detector

aNOvA is a long-baseline neutrino oscillation experiment that uses the NuMI beam from Fermilab. Its physics goals include providing constraints to the neutrino mass hierarchy and the CP-violating phase $\delta$ by precision measurements of the electron (anti)neutrino appearance in a muon (anti)neutrino beam. Similarly, new limits on the values of $\sin^2{\theta_{23}}$ and $\Delta m^{2}_{32}$ will be achieved by measurements of the muon (anti)neutrino disappearance probabilities. A combined analysis measurement will allow a better resolution of the $\theta_{23}$ octant. The NuMI beam is produced by the collision of high energy protons into a target, giving rise to kaon and pion mesons that decay to neutrinos of a specific flavor. This thesis presents a measurement of the kaon production normalization scale using uncontained charged-current muon neutrinos at the Far Detector. Because the neutrino beam is not pure in flavor, it contains an admixture of other different n eutrino flavors that become a source of background. %in oscillation analysis. Therefore, it is of paramount importance for accelerator experiments, such as NOvA, to have a reliable flux prediction of the neutrino beam in order to achieve its physics goals. One method to constrain the flux is to constrain and measure each flux component independently. The kaon component contributes to the intrinsic $\nu_{e}$ contamination of the beam, a key background for the $\nu_{e}$-appearance analysis. We observed that the uncontained sample in the 10-20 GeV region corresponds to the kaon component of the NuMI beam at the Far Detector. We also found a 60-80\% correlation between the Near Detector $\nu_{e}$ background and the Far Detector $\nu_{\mu}$ uncontained signal. The data used for this analysis was collected from October 2014 to February 2017, corresponding to $7.99 \times 10^{20}$ protons-on-target (POT). The ratio between the Far Detector data and the simulation is fitted to a lin e in the 10-20 GeV energy region. Calibration, energy scale,! final state interactions and neutrino flux (e.g. beam transport and hadron production shape only) systematic uncertainties are considered. The kaon production normalization scale is measured to be $S_{K} = 1.07 \pm 0.16$.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Regge-plus-resonance predictions for neutral-kaon photoproduction from the deuteron

We present a Regge-inspired effective-Lagrangian framework for neutral-kaon photo-production from the deuteron. Quasi-free kaon production is investigated using the Regge-plus-resonance elementary operator within the relativistic plane-wave impulse approximation. The Regge-plus-resonance model was developed to describe photoinduced and electroinduced charged-kaon production off protons. We show how this elementary operator can be transformed to account for the production of neutral kaons from both protons and neutrons. Our results compare favourably to the sole {sup 2}H({gamma},K{sup 0})YN dataset published to date.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Kaon physics: a cornerstone for future discoveries

The kaon physics programme, long heralded as a cutting-edge frontier by the European Strategy for Particle Physics, continues to stand at the intersection of discovery and innovation in high-energy physics (HEP). With its unparalleled capacity to explore new physics at the multi-TeV scale, kaon research is poised to unveil phenomena that could reshape our understanding of the Universe. This document highlights the compelling physics case, with emphasis on exciting new opportunities for advancing kaon physics not only in Europe but also on a global stage. As an important player in the future of HEP, the kaon programme promises to drive transformative breakthroughs, inviting exploration at the forefront of scientific discovery.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Kaon gluon parton distribution and momentum fraction from 2+1+1 lattice QCD with high statistics

We present a high-statistics lattice-QCD determination of the kaon gluon parton distribution function and gluon momentum fraction. We use clover valence fermion action to take 1,296,640 kaon-correlator measurements on a highly improved staggered quark ensemble with 𝑎 ≈ 0.12 fm and 310-MeV pion mass generated by the MILC Collaboration. A detailed investigation into the impact of gauge-link smearing on the gluonic matrix elements indicates that five steps of hypercubic smearing offer an effective balance between signal quality and preservation of long-distance physics. We report a nonperturbatively renormalized kaon gluon momentum fraction of Math output error at 𝜇 = 2 GeV in the Math output error scheme. Using reduced pseudo-Ioffe-time-distribution matrix elements and pseudo-parton-distribution-function (PDF) matching, we extract the kaon gluon PDF and compare with the prediction from the Dyson-Schwinger equation and with the pion PDF obtained from the same ensemble.

First-principles calculations↗

Systematic study of charged-pion and kaon femtoscopy in Au+Au collisions at √s NN = 200 GeV

We present a systematic study of charged pion and kaon interferometry in Au+Au collisions at √s NN =200 GeV. The kaon mean source radii are found to be larger than pion radii in the outward and longitudinal directions for the same transverse mass; this difference increases for more central collisions. The azimuthal-angle dependence of the radii was measured with respect to the second-order event plane and similar oscillations of the source radii were found for pions and kaons. Hydrodynamic models qualitatively describe the similar oscillations of the mean source radii for pions and kaons, but they do not fully describe the transverse-mass dependence of the oscillations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Influence of nucleus potential on kaon and antikaon pairs decayed from short lived particles in a nucleus

We propose a possible way to probe the interactions of kaon- and antikaon-nucleus by measuring K{sup +}K{sup -} pairs decayed from {phi}(1020) meson in a nuclear target. The K{sup +}K{sup -} pairs emerged from nuclei can be affected by hadronic potentials and the difference of kaon- and antikaon-nucleus potential maybe modify invariant masses of K{sup +}K{sup -} decayed from {phi} mesons. The {phi} mesons can be produced with a lead target for the energy region 1.5{approx}2.4 GeV at LEPS facility in Super Photon Ring 8-GeV (Spring-8). By comparing results of Monte Carlo calculation with experimental data, we can probe kaon-, and antikaon-nucleus potential.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Pion and kaon structure functions at an electron-ion collider

Pions and kaons are, along with protons and neutrons, the main building blocks of nuclear matter. They are connected to the Goldstone modes of dynamical chiral symmetry breaking, the mechanism thought to generate all hadron mass in the visible universe. The distribution of the fundamental constituents, the quarks and gluons, is expected to be different in pions, kaons, and nucleons. However, experimental data are sparse. As a result, there has been persistent doubt about the behaviour of the pion's valence quark structure function at large Bjorken-$x$ and virtually nothing is known about the contribution of gluons. The Electron-Ion Collider (EIC) with an acceptance optimized for forward physics could provide access to structure functions over a larger kinematic region. This would allow for measurements testing if the origin of mass is encoded in the differences of gluons in pions, kaons, and nucleons, and measurements that could serve as a test of assumptions used in the extraction of structure functions and the pion and kaon form factors. Furthermore, measurements at an EIC would also allow to explore the effect of gluons at high x.

74 ATOMIC AND MOLECULAR PHYSICS↗

Pion and kaon valence quark distribution functions from Dyson-Schwinger equations

Using realistic quark propagators and meson Bethe-Salpeter amplitudes based on the Dyson-Schwinger equations, we calculate the pion and kaon's valence parton distribution functions (PDF) through the modified impulse approximation. The PDFs we obtained at hadronic scale have the purely valence characteristic and exhibit both dynamical chiral symmetry breaking and SU(3) flavor symmetry breaking effects. A new calculation technique is introduced to determine the valence PDFs with precision. Through next-to-leading order (NLO) evolution, our result is compared with pion and kaon valence PDF data at experimental scale. Good agreement is found in the case of pion, while deviation emerges for kaon. We point out this situation can potentially be resolved by incorporating gluon contributions into the mesons if the pion hosts more gluons than kaon nonperturbatively.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

A Study of Quark Fragmentation Using Kaons Produced in Association with Prompt $D_s^±/D^±$ Mesons

Quarks are considered to be the fundamental constituents of hadronic matter, but they have never been observed as free particles. When quarks are produced at high energy colliders, they quickly form bound colorless states, which then decay to produce the particles observed in experiments. The process by which an initially free quark combines with other quarks to form a hadronic particle is called quark fragmentation and has been described using phenomenological models since quarks were first proposed. Since then, several models have been developed to describe the quark fragmentation phenomenon, and these have been tuned to reproduce many average properties of hadrons produced in high energy collisions. In this dissertation, we describe an analysis that probes the properties of particles produced in association with a hadron containing a charm quark that provides a way, for the first time, to study what is thought of as the second particle produced in the process of heavy quar k fragmentation. Data from proton anti-proton collisions was used to carry out this research, which were collected with the CDF II detector at the Fermilab Tevatron and corresponds to 360/pb -1 of integrated luminosity. We reconstruct $D_s^±$ and $D^±$ mesons, which contain charm quarks, and identify the kaons produced in association with them. The kinematic properties of these kaons are compared with predictions of the fragmentation models implemented in the PYTHIA and HERWIG event generators. We find that kaon production in association with $D_s^±$ mesons is enhanced at levels that are in agreement with the fragmentation models but observe differences in production rates of kaons that are produced later in the fragmentation process.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Exclusive Kaon Electroproduction in Hall C at JLab 12 GeV and EIC

The additional flavor degree of freedom in the H($e,e^\prime K^+$)$\Lambda$/$\Sigma^0$ reactions provides a unique opportunity to study the mechanism underlying strangeness production and the transition from hadronic to partonic degrees of freedom in exclusive processes. However, due to the lack of experimental facilities, the potential of these reactions has not been fully exploited to date. The Jefferson Lab 12 GeV upgrade provides the energies needed for precision kaon cross section measurements in the valence quark region in Hall C. A new threshold aerogel Cerenkov detection system provides a simple and economical option for the kaon identification. Beyond the valence quark region, the first studies of strange sea quarks could be carried out at a future facility like an Electron Ion Collider (EIC). A Detector of Internally Reflected Cherenkov light (DIRC) offers a geometrically compact option for particle ID over the full range of kaon momenta. In this talk I will present the current status and discuss the outlook on future studies of strange quarks with kaon electroproduction as well as the particle identification requirements for each of these stages.

Hlavin, Nathaniel↗

The electromagnetic form factor for the kaon in the light-front approach

In this paper, the kaon electromagnetic form factor is calculated with a light-front constituent quark model (LFCQM). The electromagnetic components of the current (like the component {sup J+}{sub K}{sup )} are extracted from the Feynman triangle diagram with the light-front approach. By means of the Feynmam diagram, we also obtained the electroweak decay constant and the charge radius for the kaon in the light-front approach. In this work, the kaon observables are calculated and a fairly good agreement is obtained with a very higher accuracy when compared with the experimental data.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Multidimensional measurements of beam single-spin asymmetries in semi-inclusive deep-inelastic charged-kaon electroproduction off protons in the valence region

Measurements of beam single-spin asymmetries in semi-inclusive deep-inelastic electron scattering (SIDIS) with positively charged kaons off protons have been performed with 10.6 and 10.2 GeV incident electron beams using the CLAS12 spectrometer at Jefferson Lab. We report an analysis of the electroproduction of positively charged kaons over a large kinematic range of fractional energy, Bjorken 𝑥, transverse momentum, and photon virtualities 𝑄 2 ranging from 1 GeV 2 up to 6 GeV 2 . This is the first published multidimensionally binned CLAS12 measurement of a kaon SIDIS single-spin asymmetry in the valence quark regime. The data provide constraints on the structure function ratio $𝐹^{sin \space𝜙}_{𝐿⁢𝑈}$⁡/$𝐹_{𝑈⁢𝑈}$, where $𝐹^{sin \space𝜙}_{𝐿⁢𝑈}$ is a quantity with a leading twist of twist-3 that can reveal novel aspects of the quark-gluon correlations within the nucleon. The impact of the data on understanding the underlying reaction mechanisms and their kinematic variation is explored using theoretical models for the different contributing twist-3 parton-distribution functions (PDFs) and fragmentation functions (FFs).

form factors↗

Kaon Femtoscopy with Lévy-Stable Sources from $\sqrt{s_{NN}}$ = 200 GeV Au+Au Collisions at RHIC

Femtoscopy has the capacity to probe the space-time geometry of the particle-emitting source in heavy-ion collisions. In particular, femtoscopy of like-sign kaon pairs may shed light on the origin of non-Gaussianity of the spatial emission probability density. The momentum correlations between like-sign kaon pairs are measured in data recorded by the STAR experiment, from $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions at RHIC, BNL. Preliminary results hint at the possible existence of non-Gaussian, Lévy-stable sources, with the likely presence of an anomalous diffusion process in the signal for the identically charged kaon pairs so produced. More statistically significant studies at lower centre-of-mass energies may contribute to the search for the critical end point of QCD.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Space-time evolution of particle emission in p–Pb collisions at $\sqrt{{s}_{\text{NN}}} = 5.02$ TeV with 3D kaon femtoscopy

The measurement of three-dimensional femtoscopic correlations between identical charged kaons (K ± K ± ) produced in p–Pb collisions at center-of-mass energy per nucleon pair $\sqrt{{s}_{\text{NN}}}=5.02$ TeV with ALICE at the LHC is presented for the first time. This measurement, supplementary to those in pp and Pb–Pb collisions, allows understanding the particle-production mechanisms at different charged-particle multiplicities and provides information on the dynamics of the source of particles created in p–Pb collisions, for which a general consensus does not yet exist. It is shown that the measured source sizes increase with charged-particle multiplicity and decrease with increasing pair transverse momentum. These trends for K ± K ± are similar to the ones observed earlier in identical charged-pion and ${\text{K}}_{\text{s}}^{0}{\text{K}}_{\text{s}}^{0}$ correlations in Pb–Pb collisions at various energies and in π ± π ± correlations in p–Pb collisions at $\sqrt{{s}_{\text{NN}}}=5.02$ TeV. At comparable multiplicity, the source sizes measured in p–Pb collisions agree within uncertainties with those observed in pp collisions, and there is an indication that they are smaller than those observed in Pb–Pb collisions. The obtained results are also compared with predictions from the hadronic interaction model EPOS 3, which tends to underestimate the source size for the most central collisions and agrees with the data for semicentral and peripheral events. Furthermore, the time of maximal emission for kaons is extracted. It turns out to be comparable with the value obtained in highly peripheral Pb–Pb collisions at the same energy, indicating that the kaon emission evolution is similar to that in p–Pb collisions.

Heavy Ion Experiments↗