Precision studies of few-nucleon system dynamics

Modern nucleon-nucleon interaction models can be probed quantitatively in the three-nucleon (3N) environment by comparing predictions based on rigorous solutions of the Faddeev equations with the measured observables. Proper description of the experimental data can be achieved only if the models are supplemented with additional dynamical ingredients: subtle traces of suppressed degrees of freedom, effectively introduced by means of genuine three-nucleon forces and effects of the Coulomb force. As an example of precision studies of 3N system dynamics, new generation measurements of the 1H(d→,pp) n breakup reaction at 130 MeV are considered. Large sets of high accuracy, exclusive cross-section and analyzing power data acquired in these projects contribute significantly to constrain the physical assumptions underlying the theoretical interaction models. Comparisons of the cross-section data with the predictions using nuclear interactions generated in various ways, allowed to establish importance of including both, the 3N and the Coulomb forces to strongly improve description of the whole data set. Discrepancies observed in reproducing the analyzing power data hint at still persisting incompleteness of modeling the 3N system interaction dynamics

BRP-170 and BRP190 isoforms of Bruchpilot protein differentially contribute to the frequency of synapses and synaptic circadian plasticity in the visual system of Drosophila

In the first optic neuropil (lamina) of the optic lobe of Drosophila melanogaster, two classes of synapses, tetrad and feedback, show daily rhythms in the number and size of presynaptic profiles examined at the level of transmission electron microscopy (TEM). Number of tetrad presynaptic profiles increases twice a day, once in the morning and again in the evening, and their presynaptic ribbons are largest in the evening. In contrast, feedback synapses peak at night. The frequency of synapses is correlated with size of the presynaptic element measured as the platform size of so-called T-bars, with T-bar platforms being largest with increasing synapse frequency. The large scaffold protein Bruchpilot (BRP) is a major essential constituent of T-bars, with two major isoforms of 190 and 170 kD forming T-bars of the peripheral neuromuscular junctions (NMJ) synapses and in the brain. In addition to the analysis of cyclic plasticity of tetrad and feedback synapses in wild-type flies, we used TEM to examine daily changes in the size and distribution of synapses within isoform-specific BRP mutants, expressing BRP-190 (BRPΔ170) or BRP-170 (BRPΔ190) only. We found that the number and circadian plasticity of synapses depends on both isoforms. In the BRPΔ190 lacking BRP-190 there was almost 50% less tetrad synapses demonstrable than when both isoforms were present. The lack of BRP-170 and BRP-190 increased and decreased, respectively the number of feedback synapses, indicating that BRP-190 forms most of the feedback synapses. In both mutants, the daily plasticity of tetrad and feedback presynaptic profiles was abolished, except for feedback synapses in BRPΔ190. The oscillations in the number and size of presynaptic elements seem to depend on a different contribution of BRP isoforms in a presynaptic element at different time during the day and night and at various synapse types. The participation of both BRP isoforms may vary in different classes of synapses

Experimental studies of nuclear interactions in few-nucleon systems

This article belongs to the Topical Collection "The 23rd European Conference on Few-Body Problems in Physics". This work was partially supported by Polish National Science Center from Grant DEC-2012/05/B/ST2/02556 and by the European Commission within the Seventh Framework Programme through IA-ENSAR (contract no. RII3-CT-2010-262010).Systems of three nucleons (3N) can be treated as a testing ground for modern approaches to describe nuclear interactions. At intermediate energies, observables for 3N systems are sensitive to subtle effects of the dynamics beyond the pairwise nucleon–nucleon force, so-called 3N-force (3NF). For years the search for 3NF has been motivating precise measurements of observables of elastic nucleon–deuteron scattering and for the deuteron breakup reaction. Breakup of a deuteron in collision with a proton leads to the final state of three free nucleons, with variety of possible kinematic configurations, revealing locally enhanced sensitivity to particular aspects of the interaction dynamics, like 3NF, Coulomb force between protons, or relativistic effects. This feature makes the breakup reaction a very versatile tool for validation of the theoretical description. Reactions involving four nucleons pose immense challenges with regard to exact theoretical calculations for such systems. Nonetheless, they attract attention due to expected enhanced sensitivity to certain aspects of the nuclear dynamics, manifesting themselves in various channels and configurations. The most important results of recent experimental studies of 3N and 4N systems at intermediate energies are discussed. A brief survey of the ongoing projects is given.NCN, European Commission within the Seventh Framework Programme through IA-ENSA

Invariant coordinates in breakup reactions : three nucleon force effects

Systematic experimental studies of few-nucleon systems expose various dynamical ingredients which play an important role in correct description of observables, such as three-nucleon force, Coulomb force and relativistic effects. A large set of existing experimental data for 1H(d, pp) n reaction allows for systematic investigations of these dynamical effects, which vary with energy and appear with different strength in certain observables and phase space regions. Moreover, systematic comparisons with exact theoretical calculations, done in variables related to the system dynamics in a possibly direct ways is a very important tool to verify and improve the existing description of the nucleon interaction. Examples of experimental data for a breakup reaction, transformed to the variables based on Lorentz-invariants are compared with modern theoretical calculations

Measurement of differential cross sections for the deuteron-proton breakup reaction at 160 MeV

W. Parol, A. Kozela, K. Bodek, A. Deltuva, M. Eslami-Kalantari, J. Golak, N. Kalantar-Nayestanaki, G. Khatri, St. Kistryn, J. Kubo´s, P. Kulessa, A. Magiera, H. Mardanpour, J. G. Messchendorp, I. Mazumdar, R. Skibiński, I. Skwira-Chalot, A. Ramazani-Moghaddam-Arani, D. Rozpędzik, H. Witała, B. Włoch, A. WrońskaDifferential cross sections for the deuteron breakup 1H(d, pp)n reaction were measured for a large set of 243 geometrical configurations at the beam energy of 80 MeV/nucleon. The cross-section data are normalized by the luminosity factor obtained on the basis of a simultaneous measurement of the elastic-scattering channel and the existing cross-section data for this process. The results are compared with the theoretical calculations modeling nuclear interactions with and without taking into account the three-nucleon force (3NF) and the Coulomb interaction. In the validated region of the phase space, both the Coulomb force and 3NF play an important role in providing a good description of the data. There are also regions in which description improvements due to the inclusion of 3NF are insufficient

Few-nucleon system dynamics studied via deuteron-deuteron collisions at 160 MeV

Pozostali autory: I. Ciepał, K. Bodek, N. Kalantar-Nayestanaki, G. Khatri, St. Kistryn, A. Kozela, J. Kubo´s, P. Kulessa, A. Magiera, J. Messchendorp, I. Mazumdar, W. Parol, R. Ramazani-Sharifabadi, D. Rozpedzik, I. Skwira-Chalot, B. Włoch, A. Wrońska, J. ZejmaFour nucleon scattering at intermediate energies provides unique opportunities to study effects of the two key ingredients of the nuclear dynamics, the nucleon-nucleon P-wave (NNP-wave) and the three-nucleon force (3NF). This is possible only with systematic and precise data, in conjunction with exact theoretical calculations. Using the BINA detector at KVI Groningen, the Netherlands, a rich set of differential cross section of the 2H(d, dp)n breakup reaction at 160 MeV deuteron beam energy has been measured. Besides the three-body breakup, also cross sections of the 2H(d, 3He)n proton transfer reaction have been obtained. The data are compared to the recent calculations for the threecluster breakup

Determination of phase space region for cross-check validation of the neutron detection in the BINA experiments

cd autorów: B. Włoch, K. Bodek, I Ciepał, M. Eslami-Kalantari, J. Golak, N. Kalantar-Nayestanaki, G. Khatri, St. Kistryn, A. Kozela, J. Kuboś, P. Kulessa, A. Magiera, H. Mardanpour, J. Messchendorp, I. Mazumdar, W. Parol, A. Ramazani-Moghaddam-Arani, D. Rozpędzik, R. Skibiński, I. Skwira-Chalot, H. Witała, A Wrońska, J. ZejmaDeuteron breakup reactions are basic laboratories for testing nuclear force models. Recent improvements in the data analysis allow for direct identification of neutrons in the BINA detection setup. This opens up the opportunity to study new aspects of few-nucleon system dynamics like charge dependence of nuclear force or Coulomb interaction. In this paper we determine regions along the kinematical curves where differential cross section of deuteron-proton breakup reactions can be measured by the proton-neutron and proton-proton coincidences simultaneously. This is particularly useful for validation of the neutron detection technique

Experimental study of three-nucleon dynamics in proton-deuteron breakup reaction

A measurement of the differential cross sections for the proton-deuteron elastic scattering and the deuteron breakup in collision with a proton was carried out at Cyclotron Center Bronowice using the BINA detection system. The very preliminary analysis of the experimental data taken at three proton beam energies: 108, 135 and 160 MeV is presented

Current stage of studies of the star configurations at intermediate energies with the use of the BINA detector

cd autorów: Kazimierz Bodek, Izabela Ciepał, Mohammad Eslami-Kalantari, Nasser Kalantar-Nayestanaki, Ghanshyambhai Khatri, Stanisław Kistryn, Adam Kozela, Joanna Kuboś, Paweł Kulessa, Andrzej Magiera, Hossein Mardanpour, Johan Messchendorp, Indranil Mazumdar, Wiktor Parol, Ahmad Ramazani-Moghaddam-Arani, Dagmara Rozpędzik, Izabela Skwira-Chalot, Bogusław Włoch, Aleksandra Wrońska, Jacek ZejmaThe Space Star Anomaly in proton-deuteron breakup cross-section occurs at energies of about 10 MeV. Data for higher energies are sparse. Therefore, a systematic scan over star configurations in the range of intermediate energies between 50 and 100 MeV/nucleon is carried out on the basis of data collected with the large acceptance BINA detector. The preliminary cross section results for forward star configurations at 80 MeV/nucleon slightly surpass the theoretical calculations, but the systematic uncertainties are still under study. Also, a new variable describing rotation of star configurations is proposed

Study of three-nucleon dynamics in the dp breakup collisions using the WASA detector

An experiment to investigate the 1H(d; pp)n breakup reaction using a deuteron beam of 300, 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Jülich. As a first step, the data collected at the beam energy of 340MeV are analysed, with a focus on the proton–proton coincidences registered in the Forward Detector. Elastically scattered deuterons are used for precise determination of the luminosity. The main steps of the analysis, including energy calibration, particle identification (PID) and efficiency studies, and their impact on the final accuracy of the result, are discussed