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L B Weinstein - One of the best experts on this subject based on the ideXlab platform.
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short range correlations and the nuclear emc effect in deuterium and helium 3
arXiv: High Energy Physics - Phenomenology, 2020Co-Authors: E P Segarra, Gerald A Miller, E Piasetzky, J R Pybus, F Hauenstein, D W Higinbotham, Aaron G Schmidt, M Strikman, L B WeinsteinAbstract:The EMC effect in deuterium and helium-3 is studied using a convolution formalism that allows isolating the impact of high-momentum Nucleons in short-ranged correlated (SRC) pairs. We assume that the modification of the structure function of bound Nucleons is given by a universal (i.e. nucleus independent) function of their virtuality, and find that the effect of such modifications is dominated by Nucleons in SRC pairs. This SRC-dominance of nucleon modifications is observed despite the fact that the bulk of the nuclear inelastic scattering cross-section comes from interacting with low-momentum Nucleons. These findings are found to be robust to model details including nucleon modification function parametrization, free nucleon structure function and treatment of nucleon motion effects. While existing data cannot discriminate between such model details, we present predictions for measured, but not yet published, tritium EMC effect and tagged nucleon structure functions in deuterium that are sensitive to the neutron structure functions and bound nucleon modification functions.
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modified structure of protons and neutrons in correlated pairs
Nature, 2019Co-Authors: B Schmookler, O Hen, E Piasetzky, L B Weinstein, M Duer, S Adhikari, Aaron G Schmidt, M Strikman, S Gilad, M J AmaryanAbstract:The atomic nucleus is made of protons and neutrons (Nucleons), which are themselves composed of quarks and gluons. Understanding how the quark–gluon structure of a nucleon bound in an atomic nucleus is modified by the surrounding Nucleons is an outstanding challenge. Although evidence for such modification—known as the EMC effect—was first observed over 35 years ago, there is still no generally accepted explanation for its cause1,2,3. Recent observations suggest that the EMC effect is related to close-proximity short-range correlated (SRC) nucleon pairs in nuclei4,5. Here we report simultaneous, high-precision measurements of the EMC effect and SRC abundances. We show that EMC data can be explained by a universal modification of the structure of Nucleons in neutron–proton SRC pairs and present a data-driven extraction of the corresponding universal modification function. This implies that in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have distorted quark structure. This universal modification function will be useful for determining the structure of the free neutron and thereby testing quantum chromodynamics symmetry-breaking mechanisms and may help to discriminate between nuclear physics effects and beyond-the-standard-model effects in neutrino experiments.
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center of mass motion of short range correlated nucleon pairs studied via the a e e pp reaction
Physical Review Letters, 2018Co-Authors: Eliahu Cohen, O Hen, E Piasetzky, L B Weinstein, M Duer, Aaron J Schmidt, I Korover, H Hakobyan, S Adhikari, Z AkbarAbstract:Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all Nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the Nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field Nucleons in specific quantum states.
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nucleon nucleon correlations short lived excitations and the quarks within
Reviews of Modern Physics, 2017Co-Authors: O Hen, Gerald A Miller, E Piasetzky, L B WeinsteinAbstract:This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. We focus on the interpretation of measurements of the EMC effect for valence quarks, a reduction in the Deep Inelastic Scattering (DIS) cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon Short-Range Correlations (SRC) in nuclei. Our review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRC that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual Nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the Nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein.
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the emc effect and high momentum Nucleons in nuclei
International Journal of Modern Physics E-nuclear Physics, 2013Co-Authors: O Hen, Gerald A Miller, E Piasetzky, D W Higinbotham, L B WeinsteinAbstract:Recent developments in understanding the influence of the nucleus on deep-inelastic structure functions, the EMC effect, are reviewed. A new data base which expresses ratios of structure functions in terms of the Bjorken variable xA = AQ2/(2MA q0) is presented. Information about two-nucleon short-range correlations (SRC) from experiments is also discussed and the remarkable linear relation between SRC and the EMC effect is reviewed. A convolution model that relates the underlying source of the EMC effect to modification of either the mean-field Nucleons or SRC Nucleons is presented. It is shown that both approaches are equally successful in describing the current EMC data.
Maxim Pospelov - One of the best experts on this subject based on the ideXlab platform.
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electric dipole moments as probes of new physics
Annals of Physics, 2005Co-Authors: Maxim Pospelov, Adam RitzAbstract:We review several aspects of flavour-diagonal CP-violation, focussing on the role played by the electric dipole moments (EDMs) of leptons, Nucleons, atoms, and molecules, which constitute the source of several stringent constraints on new CP-violating physics. We dwell specifically on the calculational aspects of applying the hadronic EDM constraints, reviewing in detail the application of QCD sum-rules to the calculation of nucleon EDMs and CP-odd pion–nucleon couplings. We also consider the current status of EDMs in the Standard Model, and on the ensuing constraints on the underlying sources of CP-violation in physics beyond the Standard Model, focussing on weak-scale supersymmetry.
E Piasetzky - One of the best experts on this subject based on the ideXlab platform.
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short range correlations and the nuclear emc effect in deuterium and helium 3
arXiv: High Energy Physics - Phenomenology, 2020Co-Authors: E P Segarra, Gerald A Miller, E Piasetzky, J R Pybus, F Hauenstein, D W Higinbotham, Aaron G Schmidt, M Strikman, L B WeinsteinAbstract:The EMC effect in deuterium and helium-3 is studied using a convolution formalism that allows isolating the impact of high-momentum Nucleons in short-ranged correlated (SRC) pairs. We assume that the modification of the structure function of bound Nucleons is given by a universal (i.e. nucleus independent) function of their virtuality, and find that the effect of such modifications is dominated by Nucleons in SRC pairs. This SRC-dominance of nucleon modifications is observed despite the fact that the bulk of the nuclear inelastic scattering cross-section comes from interacting with low-momentum Nucleons. These findings are found to be robust to model details including nucleon modification function parametrization, free nucleon structure function and treatment of nucleon motion effects. While existing data cannot discriminate between such model details, we present predictions for measured, but not yet published, tritium EMC effect and tagged nucleon structure functions in deuterium that are sensitive to the neutron structure functions and bound nucleon modification functions.
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modified structure of protons and neutrons in correlated pairs
Nature, 2019Co-Authors: B Schmookler, O Hen, E Piasetzky, L B Weinstein, M Duer, S Adhikari, Aaron G Schmidt, M Strikman, S Gilad, M J AmaryanAbstract:The atomic nucleus is made of protons and neutrons (Nucleons), which are themselves composed of quarks and gluons. Understanding how the quark–gluon structure of a nucleon bound in an atomic nucleus is modified by the surrounding Nucleons is an outstanding challenge. Although evidence for such modification—known as the EMC effect—was first observed over 35 years ago, there is still no generally accepted explanation for its cause1,2,3. Recent observations suggest that the EMC effect is related to close-proximity short-range correlated (SRC) nucleon pairs in nuclei4,5. Here we report simultaneous, high-precision measurements of the EMC effect and SRC abundances. We show that EMC data can be explained by a universal modification of the structure of Nucleons in neutron–proton SRC pairs and present a data-driven extraction of the corresponding universal modification function. This implies that in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have distorted quark structure. This universal modification function will be useful for determining the structure of the free neutron and thereby testing quantum chromodynamics symmetry-breaking mechanisms and may help to discriminate between nuclear physics effects and beyond-the-standard-model effects in neutrino experiments.
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center of mass motion of short range correlated nucleon pairs studied via the a e e pp reaction
Physical Review Letters, 2018Co-Authors: Eliahu Cohen, O Hen, E Piasetzky, L B Weinstein, M Duer, Aaron J Schmidt, I Korover, H Hakobyan, S Adhikari, Z AkbarAbstract:Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all Nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the Nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field Nucleons in specific quantum states.
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nucleon nucleon correlations short lived excitations and the quarks within
Reviews of Modern Physics, 2017Co-Authors: O Hen, Gerald A Miller, E Piasetzky, L B WeinsteinAbstract:This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. We focus on the interpretation of measurements of the EMC effect for valence quarks, a reduction in the Deep Inelastic Scattering (DIS) cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon Short-Range Correlations (SRC) in nuclei. Our review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRC that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual Nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the Nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein.
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the emc effect and high momentum Nucleons in nuclei
International Journal of Modern Physics E-nuclear Physics, 2013Co-Authors: O Hen, Gerald A Miller, E Piasetzky, D W Higinbotham, L B WeinsteinAbstract:Recent developments in understanding the influence of the nucleus on deep-inelastic structure functions, the EMC effect, are reviewed. A new data base which expresses ratios of structure functions in terms of the Bjorken variable xA = AQ2/(2MA q0) is presented. Information about two-nucleon short-range correlations (SRC) from experiments is also discussed and the remarkable linear relation between SRC and the EMC effect is reviewed. A convolution model that relates the underlying source of the EMC effect to modification of either the mean-field Nucleons or SRC Nucleons is presented. It is shown that both approaches are equally successful in describing the current EMC data.
O Hen - One of the best experts on this subject based on the ideXlab platform.
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modified structure of protons and neutrons in correlated pairs
Nature, 2019Co-Authors: B Schmookler, O Hen, E Piasetzky, L B Weinstein, M Duer, S Adhikari, Aaron G Schmidt, M Strikman, S Gilad, M J AmaryanAbstract:The atomic nucleus is made of protons and neutrons (Nucleons), which are themselves composed of quarks and gluons. Understanding how the quark–gluon structure of a nucleon bound in an atomic nucleus is modified by the surrounding Nucleons is an outstanding challenge. Although evidence for such modification—known as the EMC effect—was first observed over 35 years ago, there is still no generally accepted explanation for its cause1,2,3. Recent observations suggest that the EMC effect is related to close-proximity short-range correlated (SRC) nucleon pairs in nuclei4,5. Here we report simultaneous, high-precision measurements of the EMC effect and SRC abundances. We show that EMC data can be explained by a universal modification of the structure of Nucleons in neutron–proton SRC pairs and present a data-driven extraction of the corresponding universal modification function. This implies that in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have distorted quark structure. This universal modification function will be useful for determining the structure of the free neutron and thereby testing quantum chromodynamics symmetry-breaking mechanisms and may help to discriminate between nuclear physics effects and beyond-the-standard-model effects in neutrino experiments.
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center of mass motion of short range correlated nucleon pairs studied via the a e e pp reaction
Physical Review Letters, 2018Co-Authors: Eliahu Cohen, O Hen, E Piasetzky, L B Weinstein, M Duer, Aaron J Schmidt, I Korover, H Hakobyan, S Adhikari, Z AkbarAbstract:Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all Nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the Nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field Nucleons in specific quantum states.
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nucleon nucleon correlations short lived excitations and the quarks within
Reviews of Modern Physics, 2017Co-Authors: O Hen, Gerald A Miller, E Piasetzky, L B WeinsteinAbstract:This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. We focus on the interpretation of measurements of the EMC effect for valence quarks, a reduction in the Deep Inelastic Scattering (DIS) cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon Short-Range Correlations (SRC) in nuclei. Our review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRC that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual Nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the Nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein.
-
the emc effect and high momentum Nucleons in nuclei
International Journal of Modern Physics E-nuclear Physics, 2013Co-Authors: O Hen, Gerald A Miller, E Piasetzky, D W Higinbotham, L B WeinsteinAbstract:Recent developments in understanding the influence of the nucleus on deep-inelastic structure functions, the EMC effect, are reviewed. A new data base which expresses ratios of structure functions in terms of the Bjorken variable xA = AQ2/(2MA q0) is presented. Information about two-nucleon short-range correlations (SRC) from experiments is also discussed and the remarkable linear relation between SRC and the EMC effect is reviewed. A convolution model that relates the underlying source of the EMC effect to modification of either the mean-field Nucleons or SRC Nucleons is presented. It is shown that both approaches are equally successful in describing the current EMC data.
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the emc effect and high momentum Nucleons in nuclei
arXiv: Nuclear Theory, 2013Co-Authors: O Hen, Gerald A Miller, E Piasetzky, D W Higinbotham, L B WeinsteinAbstract:Recent developments in understanding the influence of the nucleus on deep-inelastic structure functions, the EMC effect, are reviewed. A new data base which expresses ratios of structure functions in terms of the Bjorken variable $x_A=AQ^2/(2M_A q_0)$ is presented. Information about two-nucleon short-range correlations from experiments is also discussed and the remarkable linear relation between short-range correlations and teh EMC effect is reviewed. A convolution model that relates the underlying source of the EMC effect to modification of either the mean-field Nucleons or the short-range correlated Nucleons is presented. It is shown that both approaches are equally successful in describing the current EMC data.
Shaun Newman - One of the best experts on this subject based on the ideXlab platform.
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Experimental limit on an exotic parity-odd spin- and velocity-dependent interaction using an optically polarized vapor.
Nature communications, 2019Co-Authors: Young-jin Kim, Pinghan Chu, Igor Savukov, Shaun NewmanAbstract:Exotic spin-dependent interactions between fermions have recently attracted attention in relation to theories beyond the Standard Model. The exotic interactions can be mediated by hypothetical fundamental bosons which may explain several unsolved mysteries in physics. Here we expand this area of research by probing an exotic parity-odd spin- and velocity-dependent interaction between the axial-vector electron coupling and the vector nucleon coupling for polarized electrons. This experiment utilizes a high-sensitivity atomic magnetometer, based on an optically polarized vapor that is a source of polarized electrons, and a solid-state mass containing unpolarized Nucleons. The atomic magnetometer can detect an effective magnetic field induced by the exotic interaction between unpolarized Nucleons and polarized electrons. We set an experimental limit on the electron-nucleon coupling $$g_{\mathrm{A}}^{\mathrm{e}}g_{\mathrm{V}}^{\mathrm{N}} \, < \, 10^{ - 30}$$ at the mediator boson mass below 10−4 eV, significantly improving the current limit by up to 17 orders of magnitude. Symmetry breaking is an important process in fundamental understanding of matter and dark matter. Here the authors discuss an experimental bound on an exotic parity odd spin- and velocity-dependent interaction between electron and nucleon by using a sensitive spin-exchange relaxation-free atomic magnetometer.
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experimental limit on an exotic parity odd spin and velocity dependent interaction using an optically polarized vapor
arXiv: High Energy Physics - Experiment, 2019Co-Authors: Young-jin Kim, Igor Savukov, P H Chu, Shaun NewmanAbstract:Exotic spin-dependent interactions between fermions have recently attracted attention in relation to theories beyond the Standard Model. The exotic interactions can be mediated by hypothetical fundamental bosons which may explain several unsolved mysteries in physics. Here we expand this area of research by probing an exotic parity-odd spin- and velocity-dependent interaction between the axial-vector electron coupling and the vector nucleon coupling for polarized electrons. This experiment utilizes a high-sensitivity atomic magnetometer, based on an optically polarized vapor that is a source of polarized electrons, and a solid-state mass containing unpolarized Nucleons. The atomic magnetometer can detect an effective magnetic field induced by the exotic interaction between unpolarized Nucleons and polarized electrons. We set an experimental limit on the electron-nucleon coupling $g_\text{A}^\text{e} g_\text{V}^\text{N}<$ $10^{-30}$ at the mediator boson mass below $10^{-4}$ eV, significantly improving the current limit by up to 17 orders of magnitude.
