The region of high baryonic densities of the QCD phase diagram is the object of several studies focused on the investigation of the order of the phase transition and the search for the critical point. The rare probes, which include electromagnetic observables and heavy quark production, are experimentally challenging to access as they require large integrated luminosities that could be studied with fixed-target experiments. A future experiment, NA60+ at CERN, is being proposed to access this region and perform accurate measurements of the dimuon spectrum up to the charmonium region and study charm and strange hadrons. With its high beam intensity, the CERN SPS can cover the center-of-mass collision energy region from 6 to 17 GeV providing access to rare observables which have been scarcely studied until now. The proposed experiment includes a muon spectrometer based on tracking gas detectors coupled to a vertex spectrometer based on Si detectors. The time slot after the Long Shutdown 3 of the LHC (past 2029) is aimed for the first data-taking, with Pb and proton beams. In this contribution, we review the project and recent R&D effort, including the technical aspects and the studies of the physics performances for the observables.
Searches for heavy neutrinos can be successfully performed by fixed target experiments at the CERN SPS. New results obtained by the NA62 and NA48/2 kaon experiments are summarized in this paper. The physics potential of future projects exploiting SPS protons with beam dump facilities to enlarge the sensitivity to heavy neutrinos above the kaon mass limit are also outlined.
NA64 is a fixed target experiment at the CERN SPS designed as a hermetic general purpose detector to search for Dark Sector physics in missing energy events from electron/positron, hadrons, and muon scattering off nuclei. In this contribution to the FIPs 2022 workshop, we review the current status and prospects of NA64.
The phenomenology in the neutrino sector requires physics beyond the Standard Model. One possibility is the existence of new massive leptonic states which could be probed at the high intensity machines. The present results on heavy neutral leptons from the study of kaon decays in flight with the NA48/2 and NA62 experiments are presented and the future prospects for such searches at CERN SPS are discussed.
In this article the NA61/SHINE detector will be presented which is a large acceptance hadron spectrometer at the CERN SPS. It allows for a precise study of particle production from interactions of a 30 GeV proton beam in a carbon target in order to predict the neutrino flux of the T2K experiment at J-PARC, Japan. Requirements for the T2K experiment will be discussed together with the ongoing NA61 measurements. In particular preliminary NA61 results on pion production and cross section measurements from the 2007 pilot run will be shown.
The study of dilepton and direct photon emission was one of the main topics of the experimental program at the SPS devoted to the search of signals for QGP formation. Three generations of experiments, Helios-3, NA38/NA50, CERES and NA60 measured e+e- or mu+mu- production in various colliding systems and at different energies. While lepton pair production in p-A collisions was found to be reasonably well described by the expected sources, all experiments observed in nuclear collisions an excess of the yield above the extrapolation from p-A. As a result of this joint experimental effort we have …
Recent results a future prospects of the NA62 experiment at CERN SPS are presented. The NA62 experiment performed the most precise measurement of the ratio $R_K$ of the $K^+\rightarrow e^\pmν$ and K^+\rightarrow μ^\pmν$ decay rates using the full data set collected in 2007. The result is in agreement with the Standard Model expectation. The ultra-rare decay $K^+\rightarrowπ^+ν\barν$ is an excellent processes to make tests of new physics at the highest scale complementary to the LHC thanks to their theoretically cleanness. The NA62 experiment at CERN SPS aims to collect of the order of 100 $K^+…
The NA62 experiment at SPS is a continuation of the long standing CERN kaon physics program. The high statistics and the unprecedent precision allow to probe the Standard Model and test the description of the strong interactions at low energy. The final results on the the lepton universality test by measuring the ratio $R_K = Γ(K^{+}\to e^{+}ν) / Γ(K^{+}\to μ^{+}ν)$ and the study of the $K^\pm\toπ^{\pm}γγ$ decay are presented. The major goal of the NA62 experiment is to perform a measurement of the $Br(K^{+} \to π^{+} ν\barν)$ with a precision of 10% in two years of data taking. The detector s…
NA 48/2收集了最大量的$K\to3 π$。对CP破坏效应敏感的电荷不对称性参数$A_g$，在三电荷π介子模（“带电”模）和两个中性π介子处于终态的模（“中性”模）中均得到了$10^{-4}$（初步）的测量精度.我们将讨论“中性”模式下的Dalitz图结构，以指出带电π介子再散射的影响。本文将介绍荷电模式下Dalitz图参数的新的初步测量结果
We are investigating the feasibility of performing a measurement of $BR(K_L\rightarrowπ^0ν\barν)$ using a high-energy secondary neutral beam at the CERN SPS in a successor experiment to NA62. The timescale would require many years; we assume that the experiment would be ready at the start of LHC Run 4. Some preliminary conclusions from our feasibility studies, design challenges faced and sensitivity obtainable for the measurement are here presented.
我们提出的最终结果实验NA 50的Charmonia生产在铅铅相互作用在158 A GeV。随着中心性的增加，观察到一个强大的增加抑制，对于JPSI和PSIPRIME共振。我们也提出了新的发展，关于jpsi和psiprime正常的核吸收测定推导出的质子核数据。它们与Pb-Pb结果的比较使我们能够得出结论，jpsi异常抑制集在中间中心，而S-U结果显示出与p-A行为的合理一致性。在S-U相互作用中，psiprime已经受到了明显更强的抑制，这在Pb-Pb系统中不断增加，并且与从p-A碰撞推导出的预期行为完全不相容。
In the DsTau experiment at the CERN SPS, an independent and direct way to measure tau neutrino production following high energy proton interactions was proposed. As the main source of tau neutrinos is a decay of Ds mesons, produced in proton-nucleus interactions, the project aims at measuring a differential cross section of this reaction. The experimental method is based on a use of high resolution emulsion detectors for effective registration of events with short lived particle decays. Here we present the motivation of the study, details of the experimental technique, and the first results of…
The onset of the anomalous J/psi suppression in Pb-Pb collisions at the CERN SPS
NA 50实验观测到的J/psi抑制是158 AGeV的Pb-Pb碰撞中夸克-胶子等离子体形成的最显著特征之一。J/psi的生产已被研究作为一个函数的碰撞中心估计通过前向能量EZDC中释放的零度量热计（ZDC）。研究碰撞中参与核子的数量、Npart和EZDC之间的相关性，可以检查J/psi抑制模式与EZDC是否与表示为Npart函数的突然J/psi抑制机制兼容。
The centrality dependence of rapidity distributions of pions in Pb+Pb reactions can be understood by imposing local energy-momentum conservation in the longitudinal "fire-streaks" of excited matter. With no tuning nor adjustment to the experimental data, the rapidity distribution of pions produced by the fire-streak which we obtained from Pb+Pb collisions reproduces the shape of the experimental pion rapidity distribution in p+p interactions, measured by the NA49 Collaboration at the same energy. The observed difference in the absolute normalization of this distribution can be explained by the…
Multiplicity fluctuations were investigated in Ar+Sc collisions at 13A, 19A, 30A, 40A, 75A, 150A GeV/c using the NA61/SHINE detector at the SPS. Centrality selection is based on the nucleon-spectator energy in the forward hemisphere as measured by the Projectile spectator detector. Preliminary results on the scaled variance ω and the strongly intensive measure Ω were obtained for the multiplicity distribution of all, negatively and positively charged hadrons. Results are discussed and compared with p+p results and Pb+Pb data of NA49 and EPOS 1.99 simulations.
The availability of high intensity kaon beams at the CERN SPS North Area gives rise to unique possibilities for sensitive tests of the Standard Model in the quark flavor sector. Precise measurements of the branching ratios for the flavor-changing neutral current decays $K\toπν\barν$ can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. Building on the success of the NA62 experiment, plans are taking shape at CERN for a comprehensive program that will include experimental phases to measure the branching ratio for $K^+\toπ^+ν\barν$ to ~5% and to $K_L\toπ^0ν\…
Experiments at the CERN SPS: first signals of deconfinement
INFN Padova（意大利国家核物理研究所帕多瓦分部）；CERN（欧洲核子研究组织）；Jan Kochanowski University（扬·科哈诺夫斯基大学）；Universidad Nacional Autonoma de Mexico（墨西哥国立自治大学）；Czech Technical University (ČVUT)（捷克理工大学）；INFN Torino（意大利国家核物理研究所都灵分部）；Weizmann Institute of Science（魏茨曼科学研究所）；University of Cagliari（卡利亚里大学）；INFN Cagliari（意大利国家核物理研究所卡利亚里分部）
An important approach to studying high-energy cosmic rays is the investigation of the properties of extensive air showers; however, the lateral distribution of particles in simulations of such showers strongly depends on the applied model of low-energy hadronic interactions. It has been shown that many constraints to be applied to these models can be obtained by studying identified-particle spectra from accelerator collisions, in the energy range of the CERN Super Proton Synchrotron. Here we present measurements of the pion production cross-section obtained by the NA61/SHINE experiment at the …
The Search for Hidden Particles (SHiP) Collaboration has shown that the CERN SPS accelerator with its 400 $\mathrm{\small GeV/c}$ proton beam offers a unique opportunity to explore the Hidden Sector. The proposed experiment is an intensity frontier experiment which is capable of searching for hidden particles through both visible decays and through scattering signatures from recoil of electrons or nuclei. The high-intensity experimental facility developed by the SHiP collaboration is based on a number of key features and developments which provide the possibility of probing a large part of the…
The Chinese large-area violet-light-sensitive silicon photodiode PIN is one of the candidates of the lead tungstate crystal detector readout component of the photon spectrometer in the large heavy ion collision experiment. The PIN diode was assembled with the lead tungstate crystal and the low-noise preamplifier into a complete detector unit. The beam test was carried out on the SPS accelerator at CERN. The energy resolution was measured with the electron beam energy ranging from 5 to 40 GeV. The summation correction method was discussed, and an excellent linearity of the nominal beam energy v…
Results are presented for directed flow of negatively charged pions measured relative to the spectator plane in Pb+Pb collisions at the beam energy 40A GeV recorded by the NA49 experiment at CERN. The measure-ments were performed as a function of rapidity and transverse momentum in two classes of collision centrality. The projectile spectator symmetry plane is estimated using the transverse segmentation of the forward hadron calorimeters. Analysis details related to event selection and particle dentification are provided along with a description of the procedure used to apply corrections for t…
The NA61/SHINE experiment aims to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. These goals are to be achieved by performing a two dimensional phase diagram (T-μ_B) scan by measurements of hadron production properties in proton-proton, proton-nucleus and nucleus-nucleus interactions as a function of collision energy and system size. Close to the critical point an increase of fluctuations is predicted. In this contribution preliminary results on transverse momentum fluctuations and two-particle pseudorapidity/azimuthal angle c…
The problem of pinning down the critical point of strongly interacting matter still puzzles the community. One of the answers suspected to emerge in the near future will surely come from NA61/SHINE - a fixed-target experiment aiming to discover the critical point as well as to study the properties of the onset of deconfinement. This goal will be pursued by obtaining precise data on hadron production in proton-proton, proton-nucleus and nucleus-nucleus interactions in a wide range of system size and collision energy. This contribution presents new results on inclusive spectra of identified hadr…
With the Large Hadron Collider entering its third year of granting us insight into the highest collision energies to date, one should nevertheless keep in mind the unexplored physics potential of lower energies. A prime example here is the NA61/SHINE experiment at the CERN Super Proton Synchrotron. Using its large-acceptance hadronic spectrometer, SHINE aims to accomplish a number of physics goals: measuring spectra of identified hadrons in hadron-nucleus collisions to provide reference for accelerator neutrino experiments and cosmic-ray observatories, investigating particle properties in the …
Precise measurements of the branching ratios for the flavor-changing neutral current decays $K\toπν\barν$ can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. It is important to measure both decay modes, $K^+\toπ^+ν\barν$ and $K_L\toπ^0ν\barν$, since different new physics models affect the rates for each channel differently. The NA62 experiment at the CERN SPS will measure the BR for the charged channel to better than 20%. The BR for the neutral channel has never been measured. We are designing the KLEVER experiment to measure BR($K_L\toπ^0ν\barν$) to $\s…
