Charged Kaon Mass Measurement using the Cherenkov Effect
The MIPP Collaboration, N. Graf, A. Lebedev, R. J. Abrams, U. Akgun, G. Aydin, W. Baker, P. D. Barnes, T. Bergfeld, L. Beverly, A. Bujak, D. Carey, C. Dukes, F.… 展开作者
The MIPP Collaboration, N. Graf, A. Lebedev, R. J. Abrams, U. Akgun, G. Aydin, W. Baker, P. D. Barnes, T. Bergfeld, L. Beverly, A. Bujak, D. Carey, C. Dukes, F. Duru, G. J. Feldman, A. Godley, E. Gülmez, Y. O. Günaydın, H. R. Gustafson, L. Gutay, E. Hartouni, P. Hanlet, S. Hansen, M. Heffner, C. Johnstone, D. Kaplan, O. Kamaev, J. Kilmer, J. Klay, M. Kostin, D. Lange, J. Ling, M. J. Longo, L. C. Lu, C. Materniak, M. D. Messier, H. Meyer, D. E. Miller, S. R. Mishra, K. Nelson, T. Nigmanov, A. Norman, Y. Onel, J. M. Paley, H. K. Park, A. Penzo, R. J. Peterson, R. Raja, D. Rajaram, D. Ratnikov, C. Rosenfeld, H. Rubin, S. Seun, N. Solomey, R. Soltz, E. Swallow, R. Schmitt, P. Subbarao, Y. Torun, T. E. Tope, K. Wilson, D. Wright, K. Wu
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6 pages, 7 figures. Submitted to Nuclear Instruments and Methods A
最近两次精确测量带电K介子质量的方法是使用K介子原子的X射线，测量结果的不确定度分别为14 ppm和22 ppm，但彼此相差122 ppm。我们描述了一个独立的质量测量的可能性，使用切伦科夫光的测量从一个窄带光束的K介子，π介子和质子。费米国家加速器实验室（Fermi National Accelerator Laboratory）的主注入器粒子产生实验（Main Injector Particle Production experiment）记录了动量从+37 GeV/c到+63 GeV/c的质子、K介子和π介子的束流，并利用这些数据展示了这种技术。测量值为491.3 +/- 1.7 MeV/c^2，与世界平均值相差1.4 sigma。两个数量级的精度的改进将使这种技术用于解决X射线数据中的模糊性，并且可以在专用实验中实现。
英文摘要：
The two most recent and precise measurements of the charged kaon mass use X-rays from kaonic atoms and report uncertainties of 14 ppm and 22 ppm yet differ from each other by 122 ppm. We describe the possibility of an independent mass measurement using the measurement of Cherenkov light from a narrow-band beam of kaons, pions, and protons. This technique was demonstrated using data taken opportunistically by the Main Injector Particle Production experiment at Fermi National Accelerator Laboratory which recorded beams of protons, kaons, and pions ranging in momentum from +37 GeV/c to +63 GeV/c. The measured value is 491.3 +/- 1.7 MeV/c^2, which is within 1.4 sigma of the world average. An improvement of two orders of magnitude in precision would make this technique useful for resolving the ambiguity in the X-ray data and may be achievable in a dedicated experiment.
This study presents the development of hydrophobic silica aerogel for use as a radiator in threshold-type Cherenkov counters. These counters are to be used for separating positrons and positive muons produced by kaon decay in the J-PARC TREK/E36 experiment. We chose to employ aerogel with a refractive index of 1.08 to identify charged particles with momenta of approximately 240 MeV/$c$, and the radiator block shape was designed with a trapezoidal cross-section to fit the barrel region surrounding the kaon stopping target in the center of the TREK/E36 detector system. Including spares, we obtai…
We present the first measurement of event-by-event fluctuations in the kaon sector in Pb-Pb collisions at $\sqrt {s_{\rm NN}}=$ 2.76 TeV with the ALICE detector at the LHC. The robust fluctuation correlator $ν_{\rm dyn}$ is used to evaluate the magnitude of fluctuations of the relative yields of neutral and charged kaons, as well as the relative yields of charged kaons, as a function of collision centrality and selected kinematic ranges. While the correlator $ν_{\rm dyn}[\rm K^+,\rm K^-]$ exhibits a scaling approximately in inverse proportion of the charged particle multiplicity, $ν_{\rm dyn}[…
Correlations of two charged identical kaons (${\rm K}^{\rm ch}{\rm K}^{\rm ch}$) are measured in pp collisions at $\sqrt{s}=7$~TeV by the ALICE experiment at the Large Hadron Collider (LHC). One-dimensional ${\rm K}^{\rm ch}{\rm K}^{\rm ch}$ correlation functions are constructed in three multiplicity and four transverse momentum ranges. The ${\rm K}^{\rm ch}{\rm K}^{\rm ch}$ femtoscopic source parameters $R$ and $λ$ are extracted. The ${\rm K}^{\rm ch}{\rm K}^{\rm ch}$ correlations show a slight increase of femtoscopic radii with increasing multiplicity and a slight decrease of radii with incr…
We investigate the results of the charged kaon multiplicities off the deuteron target from HERMES and COMPASS experiments. The discrepancy of the two data sets cannot be explained by different $Q^2$ values. Furthermore we examine the empirical parametrization of the fragmentation functions, DSS2017, and find that the agreement between the theoretical predictions and the HERMES data is less satisfactory as claimed.
Efficient and precise Cherenkov-based charged particle timing using SiPMs
Istituto Nazionale di Fisica Nucleare, Sezione di Bari（意大利国家核物理研究所巴里分部）；CERN, the European Organization for Nuclear Research（欧洲核子研究中心）；Dipartimento di Fisica “M. Merlin” dell’Università e del Politecnico di Bari（巴里大学与理工大学M. Merlin物理学系）
A measurement of the form factors of charged kaon semileptonic decays is presented, based on $4.4 \times 10^6$ $K^\pm \to π^0 e^\pm ν_e$ ($K^\pm_{e3}$) and $2.3 \times 10^6$ $K^\pm \to π^0 μ^\pm ν_μ$ ($K^\pm_{\mu3}$) decays collected in 2004 by the NA48/2 experiment. The results are obtained with improved precision as compared to earlier measurements. The combination of measurements in the $K^\pm_{e3}$ and $K^\pm_{\mu3}$ modes is also presented.
Inclusive production of charged kaons in p+p collisions at 158 GeV/c beam momentum and a new evaluation of the energy dependence of kaon production up to collider energies
The production of charged pions, kaons and (anti)protons has been measured at mid-rapidity ($-0.5 < y < 0$) in p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV using the ALICE detector at the LHC. Exploiting particle identification capabilities at high transverse momentum ($p_{\rm T}$), the previously published $p_{\rm T}$ spectra have been extended to include measurements up to 20 GeV/$c$ for seven event multiplicity classes. The $p_{\rm T}$ spectra for pp collisions at $\sqrt{s}=7$ TeV, needed to interpolate a pp reference spectrum, have also been extended up to 20 GeV/$c$ to measure the nucl…
Hyper-Kamiokande (Hyper-K) is a proposed next generation underground water Cherenkov (WCh) experiment. The far detector will measure the oscillated neutrino flux from the long-baseline neutrino experiment using 0.6 GeV neutrinos produced by a 1.3 MW proton beam at J-PARC. It has a broad program of physics and astrophysics mainly focusing on the precise measurement of the lepton neutrino mixing matrix and the CP asymmetry. The unoscillated neutrino flux will be measured by an intermediate WCh detector. One of the proposed designs is the Tokai Intermediate Tank for the Unoscillated Spectrum (TIT…
Transverse momentum ($p_{\rm{T}}$) spectra of pions, kaons, and protons up to $p_{\rm{T}} = 20$ GeV/$c$ have been measured in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV using the ALICE detector for six different centrality classes covering 0-80%. The proton-to-pion and the kaon-to-pion ratios both show a distinct peak at $p_{\rm{T}} \approx 3$ GeV/$c$ in central Pb-Pb collisions that decreases towards more peripheral collisions. For $p_{\rm{T}} > 10$ GeV/$c$, the nuclear modification factor is found to be the same for all three particle species in each centrality interval within system…
The ratio of the leptonic charged kaon decays $R_K= Γ(K^{\pm} \to e^{\pm}ν) / Γ(K^{\pm} \to μ^{\pm}ν)$ is sensitive to the structure of the week interactions and can be precisely calculated within the Standard Model. Presence of New Physics can introduce a shift on its value of the order of a percent. The NA62 experiment at CERN SPS used data from a dedicated run in 2007 to perform a measurement of this ratio and probe the lepton universality. The data analysis technique and the final results are presented.
We have searched for proton decays into a charged antilepton ($e^+$, $μ^+$) plus a meson ($η$, $ρ^0$, $ω$) and neutron decays into a charged antilepton ($e^+$, $μ^+$) plus a meson ($π^-$, $ρ^-$) using Super-Kamiokande (SK) I-IV data, corresponding to 0.316 megaton$\cdot$years of exposure. This measurement updates the previous published result by using 2.26 times more data and improved analysis methods. No significant evidence for nucleon decay has been observed and lower limits on the partial lifetime of the nucleon are obtained. The limits range from 3$\times$10$^{31}$ to 1$\times$10$^{34}$ y…
Measurement of branching fractions for two-body charmless B decays to charged pions and kaons at BABAR
We present preliminary results of a search for charmless two-body B decays to charged pions and kaons using data collected by the BABAR detector at the Stanford Linear Accelerator Center's PEP-II storage ring. In a sample of 8.8 million produced B-anti-B pairs we measure the branching fractions B(B^0 --> pi^+pi^-) = (9.3^{+2.6}_{-2.3}^{+1.2}_{-1.4}) x 10^{-6} and B(B^0 --> K^+π^-) = (12.5^{+3.0}_{-2.6}^{+1.3}_{-1.7}) x 10^{-6}, where the first uncertainty is statistical and the second is systematic. For the decay B^0 --> K^+K^- we find no significant signal and set an upper limit of B(B^0 --> …
Transverse momentum spectra of $π^{\pm}$, $\rm K^{\pm}$ and p($\bar{\rm p}$) up to $p_{\rm T}$ = 20 GeV/$c$ at mid-rapidity in pp and Pb-Pb collisions at $\sqrt{s_{\rm NN}}=$ 2.76 TeV have been measured using the ALICE detector at the Large Hadron Collider. The proton-to-pion and the kaon-to-pion ratios both show a distinct peak at $p_{\rm T} \approx 3 GeV/c$ in central Pb-Pb collisions. Below the peak, $p_{\rm T}$ < 3 GeV/$c$, both ratios are in good agreement with hydrodynamical calculations, suggesting that the peak itself is dominantly the result of radial flow rather than anomalous hadron…
The measurement of primary $π^{\pm}$, K$^{\pm}$, p and $\overline{p}$ production at mid-rapidity ($|y| <$ 0.5) in proton-proton collisions at $\sqrt{s} = 7$ TeV performed with ALICE (A Large Ion Collider Experiment) at the Large Hadron Collider (LHC) is reported. Particle identification is performed using the specific ionization energy loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/$c$ for pions, from 0.2 up to 6 GeV/$c$ for kaons and fr…
Transverse momentum spectra of charged pions, kaons, and protons are measured in proton-proton collisions at sqrt(s) = 13 TeV with the CMS detector at the LHC. The particles, identified via their energy loss in the silicon tracker, are measured in the transverse momentum range of pt ~ 0.1-1.7 GeV and rapidities abs(y) < 1. The pt spectra and integrated yields are compared to previous results at smaller sqrt(s) and to predictions of Monte Carlo event generators. The average pt increases with particle mass and charged particle multiplicity of the event. Comparisons with previous CMS results at s…
It is well known that protons and neutrons are made from constituents, called quarks and gluons, which give substructure to these particles. The goal of this project is to make measurements of the spatial distributions and the momenta of the quarks that provide a three-dimensional map of quarks in the nuclear medium. This knowledge provides the basis of our understanding of nuclear matter in terms of the dynamics of their internal constituents. This abstract focuses on the study of the contribution of the sea quarks and in particular of the strange sea to the proton spin structure. This study …
Comments on: "Measurement of Parton Distributions of Strange Quarks in the Nucleon from Charged-Kaon Production in Deep-Inelastic Scattering on the Deuteron" by the HERMES Collaboration
