Tue·Sep 10, 2019Tuesday·September 10, 2019

1. 01*

   Observation of Feynman scaling violations and evidence for a new resonance at RHIC

   L. C. Bland🇺🇸 · E. J. Brash🇺🇸 · H. J. Crawford🇺🇸 · A.A. Derevschikov🇷🇺 · K. A. Drees🇺🇸 · J. Engelage🇺🇸 · C. Folz🇺🇸 · E. G. Judd🇺🇸 · X. Li🇺🇸 · N. G. Minaev🇷🇺 · R. N. Munroe🇺🇸 · L. Nogach🇷🇺 and 10 other authors

   We report measurements of forward jets and dijets produced in Cu+Au collisions at $\sqrt{s_{NN}}=200$ GeV at the Relativistic Heavy Ion Collider. We also report dijet production cross sections in p+p collisions at $\sqrt{s}=510$ GeV. We use the invariant dijet mass to search for indications of new particles. The p+p dijet results are compatible with string fragmentation models tuned to fit LHC data. The Cu+Au jet results far exceed Feynman scaling limits, and are compatible with models that incorporate string fusion to increase parton energy, acting as a QCD accelerator. The Cu+Au dijet results can be mostly explained by double parton scattering due to a parton flux from multiple p+p interactions with $\sqrt{s}>>\sqrt{s_{NN}}$. Further indication of the increased parton energy is obtained from evidence of single- and double-${\rm Y}$(1S) production in the forward direction in Cu+Au collisions. Finally, we report evidence for the production of a new resonance, reconstructed from its dijet decay.

   nucl-ex36 citations
2. 02*

   Studies of J/$\psi$ production at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

   ALICE Collaboration

   The inclusive J/$\psi$ production in Pb-Pb collisions at the center-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV, measured with the ALICE detector at the CERN LHC, is reported. The J/$\psi$ meson is reconstructed via the dimuon decay channel at forward rapidity ($2.5<y<4$) down to zero transverse momentum. The suppression of the J/$\psi$ yield in Pb-Pb collisions with respect to binary-scaled pp collisions is quantified by the nuclear modification factor ($R_{\mathrm{AA}}$). The $R_{\mathrm{AA}}$ at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV is presented and compared with previous measurements at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV as a function of the centrality of the collision, and of the J/$\psi$ transverse momentum and rapidity. The inclusive J/$\psi$ $R_{\mathrm{AA}}$ shows a suppression increasing toward higher $p_{\mathrm{T}}$, with a steeper dependence for central collisions. The modification of the J/$\psi$ average $p_{\mathrm{T}}$ and $p_{\mathrm{T}}^2$ is also studied. Comparisons with the results of models based on a transport equation and on statistical hadronization are also carried out.

   nucl-exhep-exJHEP(2020)·82 citations
3. 03*

   Fusion reactions in the ${}^9$Be + ${}^{197}$Au system above the Coulomb barrier

   G. S. Li🇨🇳 · J. G. Wang🇨🇳 · J. Lubian🇧🇷 · H. O. Soler🇧🇷 · Y. D. Fang🇨🇳 · M. L. Liu🇨🇳 · N. T. Zhang🇨🇳 · X. H. Zhou🇨🇳 · Y. H. Zhang🇨🇳 · B. S. Gao🇨🇳 · Y. H. Qiang🇨🇳 · S. Guo🇨🇳 and 5 other authors

   The cross sections of complete fusion and incomplete fusion for the ${}^9$Be + ${}^{197}$Au system, at energies not too much above the Coulomb barrier, were measured for the first time. The online activation followed by offline $\gamma$-ray spectroscopy method was used for the derivation of the cross sections. A slightly higher value of ICF/TF ratio has been observed, compared to other systems reported in the literature with ${}^9$Be beam. The experimental data were compared with coupled channel calculations without taking into account the coupling of the breakup channel, and experimental data of other reaction systems with weakly bound projectiles. A complete fusion suppression of about 40\% was found for the ${}^9$Be + ${}^{197}$Au system, at energies above the barrier, whereas the total fusion cross sections are in agreement with the calculations.

   nucl-exnucl-thPRC(2019)·18 citations
4. 04*

   Yield ratio of neutrons to protons in ${}^{12}C(d,n{)}^{13}$N and ${}^{12}C(d,p{)}^{13}$C from 0.6 MeV to 3 MeV

   W. J. Li🇨🇳 · Y. G. Ma🇨🇳 · G. Q. Zhang🇨🇳 · X. G. Deng🇨🇳 · M. R. Huang🇨🇳 · A. Bonasera🇺🇸 · D. Q. Fang🇨🇳 · J. Q. Cao🇨🇳 · Q. Deng🇨🇳 · Y. Q. Wang🇨🇳 · Q. T. Lei🇨🇳

   The neutron yield in ${}^{12}$C(d,n)${}^{13}$N and the proton yield in ${}^{12}C(d,p{)}^{13}$C have been measured by deuteron beam from 0.6 MeV to 3 MeV which is delivered from a 4-MeV electro static accelerator bombarding on the thick carbon target. The neutrons are detected at $0°$, $24°$, $48°$ and the protons at $135°$ in the lab frame. The ratios of the neutron yield to the proton one have been calculated and can be used as an effective probe to pin down the resonances. The resonances are found at 1.4 MeV, 1.7 MeV, 2.5 MeV in ${}^{12}C(d,p{)}^{13}$C and at 1.6 MeV, 2.7 MeV in ${}^{12}$C(d,n)${}^{13}$N. This method provides a way to reduce the systematic uncertainty and helps to confirm more resonances in compound nuclei.

   nucl-exnucl-thNucl.Sci.Tech.(2019)·12 citations
5. 05*

   Evidence for rigid triaxial deformation in ${}^{76}$Ge from a model-independent analysis

   A. D. Ayangeakaa🇺🇸 · R. V. F. Janssens🇺🇸 · S. Zhu🇺🇸 · D. Little🇺🇸 · J. Henderson🇨🇦 · C. Y. Wu🇺🇸 · D. J. Hartley🇺🇸 · M. Albers🇺🇸 · K. Auranen🇫🇮 · B. Bucher🇺🇸 · M. P. Carpenter🇺🇸 · P. Chowdhury🇺🇸 and 16 other authors

   An extensive, model-independent analysis of the nature of triaxial deformation in ${}^{76}$Ge, a candidate for neutrinoless double-beta ($0\nu \beta \beta$) decay, was carried out following multi-step Coulomb excitation. Shape parameters deduced on the basis of a rotational-invariant sum-rule analysis provided considerable insight into the underlying collectivity of the ground-state and $\gamma$ bands. Both sequences were determined to be characterized by the same $\beta$ and $\gamma$ deformation parameter values. In addition, compelling evidence for low-spin, rigid triaxial deformation in ${}^{76}$Ge was obtained for the first time from the analysis of the statistical fluctuations of the quadrupole asymmetry deduced from the measured $E2$ matrix elements. These newly determined shape parameters are important input and constraints for calculations aimed at providing, with suitable accuracy, the nuclear matrix elements relevant to $0\nu \beta \beta$.

   nucl-exnucl-thPRL(2019)·61 citations
6. 06*

   Happy Birthday, Ultra-Cold Neutron!

   Hartmut Abele🇦🇹 · Tobias Jenke🇫🇷 · Hartmut Lemmel🇫🇷

   What is driving the accelerated expansion of the universe and do we have an alternative for Einstein's cosmological constant? What is dark matter made of? Do extra dimensions of space and time exist? Is there a preferred frame in the universe? To which extent is left-handedness a preferred symmetry in nature? What's the origin of the baryon asymmetry in the universe? These fundamental and open questions are addressed by precision experiments using ultra-cold neutrons. This year, we celebrate the 50th anniversary of their first production, followed by first pioneering experiments. Actually, ultra-cold neutrons were discovered twice in the same year, once in the eastern and once in the western world. For five decades now research projects with ultra-cold neutrons have contributed to the determination of the force constants of nature's fundamental interactions, and several technological breakthroughs in precision allow to address the open questions by putting them to experimental test. To mark the event and tribute to this fabulous object, we present a birthday song for ultra-cold neutrons with acoustic resonant transitions, which are based solely on properties of ultra-cold neutrons, the inertial and gravitational mass of the neutron, Planck's constant, and the local gravity. We make use of a musical intonation system that bears no relation to basic notation and basic musical theory as applied and used elsewhere but addresses two fundamental problems of music theory, the problem of reference for the concert pitch and the problem of intonation.

   nucl-exgr-qchep-phEPJ Web Conf.(2019)·1 citation
7. 07*

   Evidence of Single State Dominance in the Two-Neutrino Double-$\beta$ Decay of Se-82 with CUPID-0

   O. Azzolini🇮🇹 · J.W. Beeman🇺🇸 · F. Bellini🇮🇹 · M. Beretta🇮🇹 · M. Biassoni🇮🇹 · C. Brofferio🇮🇹 · C. Bucci🇮🇹 · S. Capelli🇮🇹 · L. Cardani🇮🇹 · P. Carniti🇮🇹 · N. Casali🇮🇹 · D. Chiesa🇮🇹 and 33 other authors

   We report on the measurement of the two-neutrino double-$\beta$ decay of ${}^{82}$Se performed for the first time with cryogenic calorimeters, in the framework of the CUPID-0~experiment. With an exposure of 9.95 kg$\times$yr of Zn${}^{82}$Se, we determine the two-neutrino double-$\beta$ decay half-life of ${}^{82}$Se with an unprecedented precision level, $T_{1/2}^{2\nu }=[8.60\pm 0.03\text{(stat.)}{}_{-0.10}^{+0.17}\text{(syst.)}]\times 10^{19}\text{yr}$. The very high signal-to-background ratio, along with the detailed reconstruction of the background sources allowed us to identify the single state dominance as the underlying mechanism of such process, demonstrating that the higher state dominance hypothesis is disfavored at the level of 5.5 $\sigma$.

   nucl-exPRL(2019)·70 citations
8. 08*

   Role of Neutron Transfer in Sub-Barrier Fusion

   Rudra N. Sahoo · Malika Kaushik · Arshiya Sood · Pawan Kumar · Swati Thakur · Arzoo Sharma · Pushpendra P. Singh · Md. Moin Shaikh · Rohan Biswas · Abhishek Yadav · Manoj K. Sharma · J. Gehlot · S. Nath · N. Madhvan

   Fusion excitation function of ${}^{35}$Cl + ${}^{130}$Te system is measured in the energy range around the Coulomb barrier and analyzed in the framework of the coupled-channels approach. The role of projectile deformation, nuclear structure, and the couplings of inelastic excitations and positive Q$-$value neutron transfer channels in sub-barrier fusion are investigated through the comparison of reduced fusion excitation functions of ${}^{35,37}$Cl +${}^{130}$Te systems. The reduced fusion excitation function of ${}^{35}$Cl + ${}^{130}$Te system shows substantial enhancement over ${}^{37}$Cl + ${}^{130}$Te system in sub-barrier energy region which is attributed to the presence of positive Q-value neutron transfer channels in ${}^{35}$Cl + ${}^{130}$Te system. Findings of this work strongly suggest the importance of +2$n$ - transfer coupling in sub-barrier fusion apart from the simple inclusion of inelastic excitations of interacting partners, and are in stark contrast with the results presented by Kohley \textit{et al.}, [Phys. Rev. Lett. 107, 202701 (2011)].

   nucl-exnucl-thPRC(2020)·28 citations
9. 09*

   Searching for ${}^4\overline{L}i$ by momentum correlation function of $\overline{p}{-}^3\overline{H}e$

   Bao-Shan Xi🇨🇳 · Zheng-Qiao Zhang🇨🇳 · Song Zhang🇨🇳 · Yu-Gang Ma🇨🇳

   The observed heaviest anti-nucleus so far is ${}^4\overline{H}e$ which is found in relativistic heavy ion collider in 2011. The yield of ${}^4\overline{L}i$ is four times bigger than that of ${}^4\overline{H}e$ according to the thermal model. From previous scattering experiment, we know that the ${}^{4}Li$ has a very short life time about $1.197\times 10^{-22}s$. It decays into ${}^{3}He$ and $p$. In experiment, the correlation function of $\overline{p}{-}^3\overline{H}e$ will offer us a method to observe ${}^4\overline{L}i$ by CPT symmetry. In this paper, we use the blast-wave model and Lednicky-Lyuboshitz analytical model to obtain a prediction of the correlation function of $\overline{p}-{}^3\overline{H}e$ with/without ${}^4\overline{L}i$ decay in Au + Au collisions at $\sqrt{S_{NN}}$ = 200 GeV. The correlation function with ${}^4\overline{L}i$ decay is found to exhibit a peak at $k^{\ast }\approx$ 0.073GeV/$c$. The results offer a guide for the experimental search for ${}^4\overline{L}i$ in relativistic heavy ion collision.

   ↳ nucl-thnucl-exPRC(2020)·10 citations
10. 10*

    Electromagnetic field from asymmetric to symmetric heavy ion collision at 200 GeV/c

    Yi-Lin Cheng🇨🇳 · Song Zhang🇨🇳 · Yu-Gang Ma🇨🇳 · Jin-Hui Chen🇨🇳 · Chen Zhong🇨🇳

    Electromagnetic fields produced in relativistic heavy-ion collisions are affected by the asymmetry of the projectile-target combination as well as the different initial configurations of the nucleus. In this study, the results of the electric and magnetic fields produced for different combinations of ions, namely ${}^{12}$C + ${}^{197}$Au, ${}^{24}$Mg + ${}^{197}$Au, ${}^{64}$Cu + ${}^{197}$Au, and ${}^{197}$Au + ${}^{197}$Au at $\sqrt{s_{NN}}=200$ GeV are demonstrated with a multi-phase transport model (AMPT). The configuration of the distribution of nucleons of ${}^{12}$C is initialized by a Woods-Saxon spherical structure, a three-$\alpha$-clustering triangular structure or a three-$\alpha$-clustering chain structure. It was observed that the electric and magnetic fields display different behavioral patterns for asymmetric combinations of the projectile and target nuclei as well as for different initial configurations of the carbon nucleus. The major features of the process are discussed.

    ↳ nucl-thnucl-exPRC(2019)·20 citations
11. 11*

    Finite-size scaling phenomenon of nuclear liquid--gas phase transition probes

    H. L. Liu🇨🇳 · Y. G. Ma🇨🇳 · D. Q. Fang🇨🇳

    Based on the isospin-dependent quantum molecular dynamics model, finite-size scaling effects on nuclear liquid--gas phase transition probes are investigated by studying the de-excitation processes of six thermal sources of different sizes with the same initial density and similar $N/Z$. Using several probes including the total multiplicity derivative ($d{M}_{tot}/dT$), second moment parameter ($M_2$), intermediate mass fragment (IMF) multiplicity ($N_{IMF}$), Fisher's power-law exponent ($\tau$), and Ma's nuclear Zipf's law exponent ($\xi$), the relationship between the phase transition temperature and the source size has been established. It is observed that the phase transition temperatures obtained from the IMF multiplicity, Fisher's exponent, and Ma's nuclear Zipf's law exponent have a strong correlation with the source size. Moreover, by employing the finite-size scaling law, the critical temperature $T_c$ and the critical exponent $\nu$ have been obtained for infinite nuclear matter.

    ↳ nucl-thnucl-exPRC(2019)·15 citations
12. 12*

    The energy and scale dependence of $\hat{q}$ and the JET puzzle

    Amit Kumar🇺🇸 · Abhijit Majumder🇺🇸 · Chun Shen🇺🇸

    We present an attempt to probe the underlying structure of the quark-gluon plasma (QGP) at high resolution, based on the extracted jet transport coefficient $\hat{q}$. We argue that the exchanged momentum $k$ between the hard parton and the medium varies over a range of scales, and for $k\ge$ 1 GeV, $\hat{q}$ can be expressed in terms of a parton distribution function (PDF). Because the mass of a QGP constituent is unknown, we define a scaling variable $x_N$ to represent the ratio of the parton momentum to the momentum of a self-contained section of the plasma which has a mass of 1 GeV. This scaling variable is used to parametrize the QGP-PDF. Calculations, based on this reconstructed $\hat{q}$ are compared to data sensitive to the hardcore of jets $i.e.,$ the single hadron suppression in terms of the nuclear modification factor $R_{AA}$ and the azimuthal anisotropy parameter $v_2$, as a function of transverse momentum $p_{\mathrm{T}}$, centrality and energy of the collision. It is demonstrated that the scale evolution of the QGP-PDF is responsible for the reduction in the normalization of $\hat{q}$ between fits to Relativistic Heavy-Ion Collider (RHIC) and Large Hadron Collider (LHC) data; a puzzle, first discovered by the JET collaboration.

    ↳ nucl-thhep-phnucl-exPRC(2020)·51 citations
13. 13*

    Impact of Uncertainties in Astrophysical Reaction Rates on Nucleosynthesis in the $\nu p$ Process

    T. Rauscher🇨🇭 · N. Nishimura🇯🇵 · G. Cescutti🇮🇹 · R. Hirschi🇬🇧 · A. St.J. Murphy🇬🇧 · C. Fröhlich🇺🇸

    The $\nu p$ process appears in proton-rich, hot matter which is expanding in a neutrino wind and may be realised in explosive environments such as core-collapse supernovae or in outflows from accretion disks. The impact of uncertainties in nuclear reaction cross sections on the finally produced abundances has been studied by applying Monte Carlo variation of all astrophysical reaction rates in a large reaction network. As the detailed astrophysical conditions of the $\nu p$ process still are unknown, a parameter study was performed, with 23 trajectories covering a large range of entropies and $Y_{\mathrm{e}}$. The resulting abundance uncertainties are given for each trajectory. The $\nu p$ process has been speculated to contribute to the light $p$ nuclides but it was not possible so far to reproduce the solar isotope ratios. It is found that it is possible to reproduce the solar ${}^{92}$Mo/${}^{94}$Mo abundance ratio within nuclear uncertainties, even within a single trajectory. The solar values of the abundances in the Kr-Sr region relative to the Mo region, however, cannot be achieved within a single trajectory. They may still be obtained from a weighted superposition of different trajectories, though, depending on the actual conditions in the production site. For a stronger constraint of the required conditions, it would be necessary to reduce the uncertainties in the 3$\alpha$ and ${}^{56}$Ni(n,p)${}^{56}$Co rates at temperatures $T>3$ GK.

    ↳ astro-ph.HEnucl-exnucl-thJPS Conf.Proc.(2020)·5 citations
14. 14*

    IRDFF-II: A New Neutron Metrology Library

    A. Trkov🇦🇹 · P.J. Griffin🇺🇸 · S.P. Simakov🇩🇪 · L.R. Greenwood🇺🇸 · K.I. Zolotarev🇷🇺 · R. Capote🇦🇹 · D.L. Aldama🇨🇺 · V. Chechev🇷🇺 · C. Destouches🇫🇷 · A.C. Kahler🇨🇭 · C. Konno🇯🇵 · M. Koštál🇨🇿 and 12 other authors

    High quality nuclear data is the most fundamental underpinning for all neutron metrology applications. This paper describes the release of version II of the International Reactor Dosimetry and Fusion File (IRDFF-II) that contains a consistent set of nuclear data for fission and fusion neutron metrology applications up to 60~MeV neutron energy. The library is intended to support: a) applications in research reactors; b) safety and regulatory applications in the nuclear power generation in commercial fission reactors; and c) material damage studies in support of the research and development of advanced fusion concepts. The paper describes the contents of the library, documents the thorough verification process used in its preparation, and provides an extensive set of validation data gathered from a wide range of neutron benchmark fields. The new \mbox{IRDFF-II} library includes 119 metrology reactions, four cover material reactions to support self-shielding corrections, five metrology metrics used by the dosimetry community, and cumulative fission products yields for seven fission products in three different neutron energy regions. In support of characterizing the measurement of the residual nuclei from the dosimetry reactions and the fission product decay modes, the present document lists the recommended decay data, particle emission energies and probabilities for 68 activation products. It also includes neutron spectral characterization data for 29 neutron benchmark fields for the validation of the library contents. The IRDFF-II library and comprehensive documentation is available online at https://www-nds.iaea.org/IRDFF/. Evaluated cross sections can be compared with experimental data and other evaluations at https://www-nds.iaea.org/exfor/endf.htm. The new library is expected to become the international reference in neutron metrology for multiple applications.

    ↳ nucl-thnucl-exNucl.Data Sheets(2020)·58 citations
15. 15*

    Measurements of production and inelastic cross sections for $\text{mbox}p+\text{mbox}C$, $\text{mbox}p+\text{mbox}Be$, and $\text{mbox}p+\text{mbox}Al$ at 60 GeV/$c$ and $\text{mbox}p+\text{mbox}C$ and $\text{mbox}p+\text{mbox}Be$ at 120 GeV/$c$

    NA61/SHINE Collaboration: A. Aduszkiewicz🇵🇱 · E.V. Andronov🇷🇺 · T. Antićić🇭🇷 · V. Babkin🇷🇺 · M. Baszczyk🇵🇱 · S. Bhosale🇵🇱 · A. Blondel🇨🇭 · M. Bogomilov🇧🇬 · A. Brandin🇷🇺 · A. Bravar🇨🇭 · W. Bryliński🇵🇱 · J. Brzychczyk🇵🇱 and 133 other authors

    This paper presents measurements of production cross sections and inelastic cross sections for the following reactions: 60 GeV/$c$ protons with C, Be, Al targets and 120 GeV/$c$ protons with C and Be targets. The analysis was performed using the NA61/SHINE spectrometer at the CERN SPS. First measurements were obtained using protons at 120 GeV/$c$, while the results for protons at 60 GeV/$c$ were compared with previously published measurements. These interaction cross section measurements are critical inputs for neutrino flux prediction in current and future accelerator-based long-baseline neutrino experiments.

    ↳ hep-exnucl-exPRD(2019)·29 citations
16. 16*

    A new Monte Carlo-based fitting method

    Paolo Pedroni (INFN, Pavia)🇮🇹 · Stefano Sconfietti (University and INFN, Pavia)🇮🇹

    We present a new fitting technique based on the parametric bootstrap method, which relies on the idea to produce artificial measurements using the estimated probability distribution of the experimental data. In order to investigate the main properties of this technique, we develop a toy model and we analyze several fitting conditions with a comparison of our results to the ones obtained using both the standard ${\chi }^2$ minimization procedure and a Bayesian approach. Furthermore, we investigate the effect of the data systematic uncertainties both on the probability distribution of the fit parameters and on the shape of the expected goodness-of-fit distribution. Our conclusion is that, when systematic uncertainties are included in the analysis, only the bootstrap procedure is able to provide reliable confidence intervals and p-values, thus improving the results given by the standard ${\chi }^2$ minimization approach. Our technique is then applied to an actual physics process, the real Compton scattering off the proton, thus confirming both the portability and the validity of the bootstrap-based fit method.

    ↳ physics.data-anhep-exhep-phnucl-ex+1J.Phys.G(2020)·12 citations
17. 17*

    $J/\psi$ Production Dynamics: Event shape, Multiplicity and Rapidity dependence in Proton+Proton Collisions at LHC energies using PYTHIA8

    Anisa Khatun🇮🇳 · Dhananjaya Thakur🇮🇳 · Suman Deb🇮🇳 · Raghunath Sahoo🇮🇳

    High-multiplicity pp collisions at the Large Hadron Collider (LHC) energies have created special importance in view of the Underlying Event (UE) observables. The recent results of LHC, such as long range angular correlation, flow-like patterns, strangeness enhancement etc. in high multiplicity events are not yet completely understood. In the same direction, the understanding of multiplicity dependence of J/$\psi$ production is highly necessary. Transverse spherocity, which is an event shape variable, helps to investigate the particle production by isolating the hard and the soft components. In the present study, we have investigated the multiplicity dependence of J/$\psi$ production at mid-rapidity and forward rapidity through the transverse spherocity analysis and tried to understand the role of jets by separating the isotropic and jetty events from the minimum bias collisions. We have analyzed the J/$\psi$ production at the mid-rapidity and forward rapidities via dielectron and dimuon channels, respectively using 4C tuned PYTHIA8 event generator. The analysis has been performed in two different center-of-mass energies: $\sqrt{s}$ = 5.02 and 13 TeV, to see the energy dependence of jet contribution to the multiplicity dependence study of J/$\psi$ production. Furthermore, we have studied the production dynamics through the dependence of thermodynamic parameters on event multiplicity and transverse spherocity.

    ↳ hep-phhep-exnucl-exnucl-thJ.Phys.G(2020)·15 citations
18. 18*

    Measurement of the muon neutrino charged-current single ${\pi }^{+}$ production on hydrocarbon using the T2K off-axis near detector ND280

    K. Abe · R. Akutsu · A. Ali · C. Alt · J. Amey · C. Andreopoulos · L. Anthony · M. Antonova · S. Aoki · A. Ariga · Y. Ashida · E.T.Atkin and 369 other authors

    We report the measurements of single and double differential cross section of muon neutrino charged-current interactions on carbon with a single positively charged pion in the final state at the T2K off-axis near detector using $5.56\times 10^{20}$ protons on target. The analysis uses data control samples for the background subtraction and the cross section signal, defined as a single negatively charged muon and a single positively charged pion exiting from the target nucleus, is extracted using an unfolding method. The model dependent cross section, integrated over the T2K off-axis neutrino beam spectrum peaking at $0.6$~GeV, is measured to be $\sigma =(11.76\pm 0.44\text{(stat)}\pm 2.39\text{(syst)})\times 10^{-40}{\text{cm}}^2$~${\text{nucleon}}^{-1}$. Various differential cross sections are measured, including the first measurement of the Adler angles for single charged pion production in neutrino interactions with heavy nuclei target.

    ↳ hep-exnucl-exPRD(2020)·54 citations
19. 19*

    Particle production and flow-like effects in small systems

    Antonio Ortiz (for the ALICE, ATLAS, CMS and LHCb Collaborations)🇲🇽

    Particle production in small systems (pp and p-Pb collisions) has unveiled unexpected collective-like behavior. In this work an overview of the current investigation on the similarities between small systems and heavy-ion collisions is presented. Recent results from the experiments at the LHC are discussed. They include measurements of multi-particle correlations, as well as, identified particle production as a function of charged-particle multiplicity density, and more recently, as a function of transverse spherocity.

    ↳ hep-exnucl-exPoS(2019)·6 citations
20. 20*

    Application of Principal Component Analysis to establish proper basis for flow studies in heavy-ion collisions

    Igor Altsybeev🇷🇺

    It is shown that Principal Component Analysis (PCA) applied to event-by-event single-particle distributions in A-A collisions allows establishing the most optimal basis for anisotropic flow studies from data itself, in contrast to manual selection of the basis functions. PCA coefficients for azimuthal particle distributions are identical to Fourier coefficients from a conventional analysis techniques. PCA applied in longitudinal dimension reveals optimal basis that is similar to Legendre polynomial series. Analysis in both dimensions simultaneously allows studying the coupling of the longitudinal structure of events with the azimuthal anisotropy of particle emission.

    ↳ nucl-thnucl-exPhys.Part.Nucl.(2020)·4 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.