Published data on the emission of charged particles following nuclear muon capture are extremely limited. In addition to its interest as a probe of the nuclear response, these data are important for the design of some current searches for lepton flavor violation. This work presents momentum spectra of protons and deuterons following $μ^{-}$ capture in aluminum. It is the first measurement of a muon capture process performed with a tracking spectrometer. A precision of better than 10% over the momentum range of 100--190 MeV/c for protons is obtained; for deuterons of 145--250 MeV/c the precision is better than 20%. The observed partial yield of protons with emission momenta above 80 MeV/c (kinetic energy 3.4 MeV) is $0.0322\pm0.0007(\text{stat})\pm0.0022(\text{syst})$ per capture, and for deuterons above 130 MeV/c (4.5 MeV) it is $0.0122\pm0.0009(\text{stat})\pm0.0006(\text{syst})$. Extrapolating to total yields gives $0.045\pm0.001(\text{stat})\pm0.003(\text{syst}) \pm 0.001(\text{extrapolation})$ per capture for protons and $0.018\pm0.001(\text{stat})\pm0.001(\text{syst})\pm 0.002(\text{extrapolation})$ for deuterons, which are the most precise measurements of these quantities to date.
The study of the Quark-Gluon Plasma created in ultrarelativistic heavy-ion collisions at the CERN-LHC is complemented by reference measurements in proton-lead (p--Pb) and proton-proton (pp) collisions, where the effects of multiple-parton interactions and hadronization beyond independent string fragmentation can be investigated. In these proceedings, we present a Bayesian unfolding procedure to reconstruct the correlation between transverse momentum ($ p_{\mathrm{T}}$) spectra of charged particles and the corresponding charged-particle multiplicities $N_{\mathrm{ch}}$. The unfolded spectra are…
The measurement of charged particle spectra in heavy ion collisions is a way to study properties of hot and dense matter created in these interactions. The centrality dependence of the spectral shape is an important tool to understand the energy loss mechanism. The ATLAS detector at the LHC accumulated integrated luminosity equal to 0.15nb^{-1} of lead-lead data at 2.76TeV per nucleon-nucleon pair. Due to the excellent capabilities of the ATLAS detector, and its stable operation in 2010 and 2011 heavy ion physics runs, these data allow measurements of the charged particle spectra and their rat…
The ATLAS detector at the LHC obtained the sample of p+Pb data at $\sqrt{s_{NN}}={}$5.02TeV with integrated luminosity of 25nb${}^{-1}$, which can be compared to the pp data obtained by interpolating pp measurements at $\sqrt{s}={}$2.76TeV and 7TeV. Due to the excellent capabilities of the ATLAS detector, and its stable operation in heavy ion as well as proton-proton physics runs, the data allow measurements of the nuclear modification factor, ratio of heavy ion charged particle spectra divided by pp reference, in different centrality classes over a wide range of rapidity. The charged particle…
The ALICE experiment features multiple particle identification systems. The measurement of the identified charged hadron $p_{t}$ spectra in proton-proton collisions at $\sqrt{s}=900$ GeV will be discussed. In the central rapidity region ($|η|<0.9$) particle identification and tracking are performed using the Inner Tracking System (ITS), which is the closest detector to the beam axis, the Time Projection Chamber (TPC) and a dedicated time-of-flight system (TOF). Particles are mainly identified using the energy loss signal in the ITS and TPC. In addition, the information from TOF is used to iden…
Transverse momentum spectra of charged particles are measured by the CMS experiment at the CERN LHC in pPb collisions at sqrt(s[NN]) = 5.02 TeV, in the range 0.4 < pt < 120 GeV and pseudorapidity abs(eta[CM]) < 1.8 in the proton-nucleon center-of-mass frame. For pt < 10 GeV, the charged-particle production is asymmetric about eta[CM] = 0, with smaller yield observed in the direction of the proton beam, qualitatively consistent with expectations from shadowing in nuclear parton distribution functions (nPDF). A pp reference spectrum at sqrt(s) = 5.02 TeV is obtained by interpolation from previou…
New data from the NA61 collaboration on the production of negative pions in p+p interactions at beam momenta between 20 and 158 GeV/c are critically compared to available results in the same energy range. It is concluded that the NA61 data show some discrepancies with the previous results. This concerns in particular the total yields, the $p_T$ integrated rapidity distributions and the double differential cross sections.
The measurement of the identified charged hadron p_t spectra using the ITS energy loss signal in the p-p data at sqrt{s}=900 GeV collected by the ALICE experiment at LHC will be discussed. It is performed using the Inner Tracking System (ITS) in stand-alone mode, both for track reconstruction and particle identification, allowing one to detect low momentum particles with p_t below 200 MeV/c. A second method using the tracks reconstructed by both the ITS and the Time Projection Chamber (TPC) has also been developed. The obtained results will be compared with the ones obtained from the TPC and f…
Semi-inclusive charged jet spectra per trigger at STAR are presented binned by event activity (EA) as determined by the Beam Beam Counter (BBC) signal in the Au-going direction. The selected EA determination is motivated by correlations between the number of charged tracks in the Time Projection Chamber (TPC) ($|η|<1$) and EA ($η_\mathrm{EA}\in[-5,-2]$) which are also presented. The jet spectra per trigger at high EA are suppressed relative to the spectra at low EA. A PYTHIA investigation refutes that the suppression results from a trivial autocorrelation between jet kinematics and the accepta…
We report a measurement of transverse momentum spectra of jets detected with the ALICE detector in Pb-Pb collisions at $\sNN=2.76$ TeV. Jets are reconstructed from charged particles using the anti-\kt jet algorithm. The transverse momentum of tracks is measured down to 150 MeV/$c$ which gives access to the low \pt fragments of the jet. The background from soft particle production is determined for each event and subtracted. The remaining influence of underlying event fluctuations is quantified by embedding different probes into heavy-ion data. The reconstructed transverse momentum spectrum is …
The ATLAS experiment at the Large Hadron Collider (LHC) measures charged hadron spectra obtained in 2010 and 2011 lead-lead LHC data taking periods with total integrated statistics of 0.15nb${}^{-1}$. The results are compared to the $pp$ spectra of charged hadrons at the same centre-of-mass energy based on the data sample with integrated luminosity of 4.2pb${}^{-1}$ obtained by the ATLAS experiment in 2011 and 2013. This allows a detailed comparison of the two collision systems in a wide transverse momentum ($0.5<p_{\mathrm{T}}<150$GeV) and pseudorapidity ($|η|<2$) ranges in different centrali…
Jets are collimated sprays of particles resulting from fragmentation of hard scattered partons. They are measured in different types of collisions at different energies to test perturbative Quantum Chromodynamic calculations and are used to study the hard scattering, fragmentation and hadronisation of partons. These phenomena, measured in simple systems such as proton--proton collisions, serve as a baseline to investigate their modifications by hot and dense nuclear matter created in high energy heavy-ion collisions. We have analysed data from minimum bias proton--proton collisions at centre o…
We report on the first measurement of the charged hadron composition in charged jets from pp collisions. The ALICE detector at the LHC was used to study charged pion, kaon and (anti-)proton production in jets. The results were extracted from $2 \times 10^8$ minimum bias events at a centre-of-mass energy of $\sqrt{s} = 7$ TeV. We present the transverse momentum ($p_{\mathrm{T}}$) spectra and reduced momentum spectra ($z^{\mathrm{ch}} \equiv p_{\mathrm{T}}^{\mathrm{track}} / p_{\mathrm{T, jet}}^{\mathrm{ch}}$) of $π$, K and p in charged jets with $p_{\mathrm{T, jet}}^{\mathrm{ch}}$ between 5 and…
Measurements of spectra of identified particles produced in jets represent an important tool for understanding the interplay of various hadronisation mechanisms which contribute to particle production in the hot and dense medium created in ultra-relativistic heavy-ion collisions. In this contribution, we present the measurements of the pT spectra of Λ baryons and K0S mesons produced in charged jets in Pb--Pb collisions at sqrt(sNN) = 2.76 TeV and in p--Pb collisions at sqrt(sNN) = 5.02 TeV. The results are obtained with the ALICE detector at the LHC, exploiting the excellent particle identific…
The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at $\sqrt{s} = 900$ GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region $(|η|<0.8)$ over the transverse momentum range $0.15<p_{\rm T}<10$ GeV/$c$. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for $|η|<0.8$ is $\left<p_{\rm T}\right>_{\rm INEL}=0.483\pm0.001$ (stat.) $\pm0.007$ (sys…
Transverse momentum ($p_{\rm T}$) spectra of charged particles at mid-pseudorapidity in Xe-Xe collisions at $\sqrt{s_{\rm NN}}$ = 5.44 TeV measured with the ALICE apparatus at the Large Hadron Collider are reported. The kinematic range $0.15 < p_{\rm T} < 50$ GeV/$c$ and $|η| < 0.8$ is covered. Results are presented in nine classes of collision centrality in the 0-80% range. For comparison, a pp reference at the collision energy of $\sqrt{s}$ = 5.44 TeV is obtained by interpolating between existing \pp measurements at $\sqrt{s}$ = 5.02 and 7 TeV. The nuclear modification factors in central Xe-…
We report the first measurement of charged pion, kaon and (anti-)proton production in jets from hadron colliders. The measurement was carried out with the ALICE detector using $2\times10^8$ minimum bias pp collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV at the LHC. We present the $π$, K and p transverse momentum ($p_\textrm{T}$) spectra, as well as the spectra of the reduced momentum (${z^\textrm{ch}\equiv p_\textrm{T}^\textrm{track}/p_\textrm{T, jet}^\textrm{ch}}$), in charged jets of $p_\textrm{T}$ between 5--20 $\textrm{GeV}/c$. The measurement is compared to Monte Carlo calculati…
The production of hadrons in heavy ions collisions at high $p_T$ provides an important information on mechanism of particle formation and constituent energy loss in medium. Such information is needed for search of a Critical Point and signatures of phase transition. Measurements by the STAR Collaboration of charged hadron production in Au+Au collisions at $\sqrt {s_{NN}}$=9.2 GeV over a wide transverse momentum $p_T=0.2-4.$ GeV/c and at mid-rapidity range are reported. It allows for a first measurement of the spectra for charged hadrons at high $p_T$ at this energy. The spectra demonstrate the…
We report the measured transverse momentum ($p_{\rm T}$) spectra of primary charged particles from pp, p-Pb and Pb-Pb collisions at a center-of-mass energy $\sqrt{s_{\rm NN}} = 5.02$ TeV in the kinematic range of $0.15<p_{\rm T}<50$ GeV/$c$ and $|η|< 0.8$. A significant improvement of systematic uncertainties motivated the reanalysis of data in pp and Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV, as well as in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV, which is also presented. Spectra from Pb-Pb collisions are presented in nine centrality intervals and are compared to a reference…
Charged particle production in deep-inelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5 < Q^2 < 100 GeV^2, and small values of Bjorken-x, 10^{-4} < x < 10^{-2}. The analysis is performed in the hadronic centre-of-mass system. The charged particle densities are measured as a function of pseudorapidity (eta^*) and transverse momentum (p_T^*) in the range 0< η^* < 5 and 0< p_T^* < 10$ GeV differentially in x and Q^2. The data are compared to predictions from different Monte Carlo generators implementing various op…
Charged-particle spectra obtained in 0.15 nb${}^{-1}$ of Pb+Pb interactions at $\sqrt{{s}_\mathsf{NN}}=2.76$TeV and 4.2 pb${}^{-1}$ of pp interactions at $\sqrt{s}=2.76$ TeV with the ATLAS detector at the LHC are presented in a wide transverse momentum ($0.5 < p_{\mathrm{T}} < 150$ GeV) and pseudorapidity ($|η|<2$) range. For Pb+Pb collisions, the spectra are presented as a function of collision centrality, which is determined by the response of the forward calorimeter located on both sides of the interaction point. The nuclear modification factors $R_{\mathrm{AA}}$ and $R_{\mathrm{CP}}$ are p…
Motivated by the excellent agreement between next-to-leading-order pQCD calculations and the inclusive jet spectra measured by CDF, we cross-check PYTHIA fragmentation functions. The convolution of the measured jet spectra with unmodified PYTHIA fragmentation functions results in reasonable agreement with the PYTHIA charged particle spectrum over the entire p_T range of interest, while there is a sizable disagreement with the measured charged particle spectrum above p_T=30 GeV/c. In an attempt to understand the source of this discrepancy, we introduce a number of increasingly different toy-mod…
Spectra of identified charged hadrons are measured in pPb collisions with the CMS detector at the LHC at sqrt(sNN) = 5.02 TeV. Charged pions, kaons, and protons in the transverse-momentum range pt approximately 0.1-1.7 GeV and laboratory rapidity abs(y) < 1 are identified via their energy loss in the silicon tracker. The average pt increases with particle mass and the charged multiplicity of the event. The increase of the average pt with charged multiplicity is greater for heavier hadrons. Comparisons to Monte Carlo event generators reveal that EPOS LHC, which incorporates additional hydrodyna…
We present a study of the inclusive charged-particle transverse momentum ($p_{\rm T}$) spectra as a function of charged-particle multiplicity density at mid-pseudorapidity, ${\rm d}N_{\rm ch}/{\rm d}η$, in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV covering the kinematic range $|η|<0.8$ and $0.15<p_{\rm{T}}<20$ GeV/$c$. The results are presented for events with at least one charged particle in $|η|<1$ (INEL$ >0$). The $p_{\rm T}$ spectra are reported for two multiplicity estimators covering different pseudorapidity regions. The $p_{\rm T}$ spectra normalized to that for INEL $>0$ show littl…
Event patterns extracted from anisotropic spectra of charged particles produced in lead-lead collisions at 2.76 TeV are investigated. We use an inverse power-law resulted from the QCD calculus to describe the transverse momentum spectrum in the hard scattering process, and a revised Erlang distribution resulted from a multisource thermal model to describe the transverse momentum spectrum and anisotropic flow in the soft excitation process. The pseudorapidity distribution is described by a three-Gaussian function which is a revision of the Landau hydrodynamic model. Thus, the event patterns at …
The charged particle transverse momentum (pT) spectra are presented for pp collisions at sqrt(s)=0.9 and 7 TeV. The data samples were collected with the CMS detector at the LHC and correspond to integrated luminosities of 231 inverse microbarns and 2.96 inverse picobarns, respectively. Calorimeter-based high-transverse-energy triggers are employed to enhance the statistical reach of the high-pT measurements. The results are compared with both leading-order QCD and with an empirical scaling of measurements at different collision energies using the scaling variable xT = 2 pT/sqrt(s) over the pT …
We collected the transverse momentum (mass) spectra of charged hadrons ($π^{-}$, $π^{+}$, $K^{-}$, $K^{+}$, $\overline{p}$, and $p$) produced in collisions over a center-of-mass energy range from 2.70 to 200 GeV (per nucleon pair). The modified Tsallis--Pareto-type function (the TP-like function) with average transverse flow velocity is used to describe the contribution of participant or constituent quarks to transverse momentum of considered hadron. The experimental spectra of $π^{\mp}$ and $K^{\mp}$ (or $\overline{p}$ and $p$) are fitted by the convolution of two (or three) TP-like functions…
The CERES/Na45 experiment at CERN SPS measured transverse momentum spectra of charged-pions in the range 1<pt<4GeV/c near mid-rapidity in 158 AGeV/c Pb-Au collisions. The invariant transverse momentum spectra are exponential over the entire observed range. The average inverse slope is 245+/- 5MeV/c, it shows a 2.4% increase with centrality of the collision over the 35% most central fraction of the cross section. The pi-/pi+ ratio is constant at 1.028+/-0.005 over the pt interval measured.
Pseudorapidity, transverse momentum, and multiplicity distributions are measured in the pseudorapidity range $|η| <$ 2.4 for charged particles with transverse momenta satisfying $p_\mathrm{T} >$ 0.5 GeV in proton-proton collisions at a center-of-mass energy of $\sqrt{s} =$ 13 TeV. Measurements are presented in three different event categories. The most inclusive of the categories corresponds to an inelastic pp data set, while the other two categories are exclusive subsets of the inelastic sample that are either enhanced or depleted in single diffractive dissociation events. The measurements ar…
Spectra of identified charged hadrons are measured in pp collisions at the LHC for sqrt(s) = 0.9, 2.76, and 7 TeV. Charged pions, kaons, and protons in the transverse-momentum range pt approximately 0.1-1.7 GeV and for rapidities abs(y) < 1 are identified via their energy loss in the CMS silicon tracker. The average pt increases rapidly with the mass of the hadron and the event charged-particle multiplicity, independently of the center-of-mass energy. The fully corrected pt spectra and integrated yields are compared to various tunes of the PYTHIA6 and PYTHIA8 event generators.
Heavy charged particles after nuclear muon capture are an important nuclear physics background to the muon-to-electron conversion experiments Mu2e and COMET, which will search for charged lepton flavor violation at an unprecedented level of sensitivity. The AlCap experiment measured the yield and energy spectra of protons, deuterons, tritons, and alpha particles emitted after the nuclear capture of muons stopped in Al, Si, and Ti in the low energy range relevant for the muon-to-electron conversion experiments. Individual charged particle types were identified in layered silicon detector packag…
In the present work, we study the recent collision energy and multiplicity dependence of the charged particle transverse momentum spectra as measured by the ALICE collaboration in $pp$ collisions at $\sqrt{s}$ = 5.02 and 13 TeV using the non-extensive Tsallis distribution and the Boltzmann-Gibbs Blast Wave (BGBW) model. A thermodynamically consistent form of the Tsallis distribution is used to extract the kinetic freeze-out parameters from the transverse momentum spectra of charged particles at mid-rapidity. In addition, a comprehensive study of fitting range dependence of transverse momentum …
The transverse momentum ($p_T$) and pseudorapidity ($η$) spectra of charged particles produced in proton-proton ($pp$) and lead-lead (Pb-Pb) collisions at the large hadron collider (LHC) are described by a hybrid model. In the model, the $p_T$ spectrum is described by a two-component distribution which contains an inverse power-law suggested by the QCD (Quantum Chromodynamic) calculus and an Erlang distribution resulted from a multisource thermal model. The $η$ spectrum is described by a Gaussian rapidity ($y$) distribution resulted from the Landau hydrodynamic model and the two-component $p_T…
As neutrino long baseline experiments enter a new domain of precision, the careful study of systematic errors due to poor knowledge of production cross sections for pions and kaons require more dedicated measurements for precise neutrino flux predictions. The cosmic ray experiments require dedicated hadron production measurements to tune simulation models used to describe air shower profiles. Among other goals, the NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) experiment at the CERN SPS aims at precision measurements (5% and below) for both neutrino and cosmic ray experiments: those will …
The inclusive spectra of charged particles measured at high transverse momenta ($p_T\gtrsim$2GeV/c) in proton-proton and proton-antiproton collisions in the range of center-of-mass energies $\sqrt{s}=200-7000$GeV are compared with next-to-leading order perturbative QCD calculations using seven recent sets of parton-to-hadron fragmentation functions (FFs). Accounting for the uncertainties in the scale choices and in the parton distribution functions, we find that most of the theoretical predictions tend to overpredict the measured LHC and Tevatron cross sections by up to a factor of two. We ide…
