Target mass corrections to matrix elements in nucleon spin structure functions

Nucleon Mass Corrections to Spin Dependent Structure Functions and Relations Between their Twist-3 Contributions

The nucleon mass corrections are calculated to all polarized structure functions for neutral and charged current deep inelastic scattering in lowest order in the coupling constant. The impact of the target mass corrections on the general relations between the twist--2 and twist--3 parts of the structure functions is studied and three new relations between the twist--3 contributions are derived. The size of nucleon mass corrections for the $g_1$ and $g_2$ structure functions are estimated.

再论对QCD中核子结构函数的辐射修正

Once More on the Radiative Corrections to the Nucleon Structure Functions in QCD

本文给出了一种用部分子分布表示的核子结构函数的次主导QCD修正的新表示。所有$~α_{s}~$校正的领先对数近似（LLA）包括在内。与文献中的类似表示相反，在我们的核子结构函数的表达式中，不包含$~O(α_{s}^{2})~$阶项。该结果在$~α_{s}~$中超出LLA的任何顺序下遗传。只属于所考虑的近似的$~O(α^{n}_{s})~$阶项存在于结构函数的这种表示中。

极化核子结构函数与核子自旋不对称性中的微扰与非微扰QCD修正

Perturbative and nonperturbative QCD corrections in polarized nucleon structure functions and spin asymmetries of nucleons

本研究计算了极化核子深度非弹性散射中的结构函数与不对称性，通过引入NNLO微扰修正及twist-3和靶质量等非微扰修正，验证了结果与实验相符，并为研究核介质效应提供了基准。

Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering

The explicit formulae for radiative correction (RC) calculation for elastic $ep$-scattering is presented. Two typical measurements of polarization observables such as beam-target asymmetry or recoil proton polarization, are considered. Possibilities to take into account realistic experimental acceptances are discussed. The Fortran code MASCARAD for providing the RC procedure is presented. Numerical analysis is done for kinematical conditions of TJNAF.

The $x$-Region of Shadowing Corrections in Nucleon Structure Functions

We discuss the experimental indications on the behaviour of F_2(x,Q^2) at small x both in proton and nuclear targets. By comparing the parametrizations of the data we conclude that shadowing correction effects in a proton target can appear at a noticeable level for x=(2 - 4)\times10^{-4} and Q^2\sim 10^1 GeV^2, namely inside the HERA regime.

NLO corrections to the twist-3 amplitude in DVCS on a nucleon in the Wandzura-Wilczek approximation: quark case

We computed the NLO corrections to twist-3, $L \to T$, flavor non-singlet amplitude in DVCS on a nucleon in the Wandzura-Wilczek approximation. Explicit calculation shows that factorization holds for NLO contribution to this amplitude, although the structure of the factorized amplitude at the NLO is more complicated than in the leading-order formula. Next-to-leading order coefficient functions for matrix elements of twist-3 vector and axial-vector quark string operators and their LO evolution equations are presented.

核子自旋结构函数对QCD Bjorken求和规则的靶质量修正

Target Mass Corrections to QCD Bjorken Sum Rule for Nucleon Spin Structure Functions

本文讨论了在极化深度非弹性轻子产生中测量的核子自旋相关结构函数的QCD分析中可能的靶质量修正。QCD Bjorken求和规则的目标质量修正是从Nachtmann矩获得的，其大小是估计采用正界以及实验数据的非对称性参数。我们还研究了由Bjorken求和规则确定QCD有效耦合常数$α_s(Q^2)$时由于靶质量效应引起的不确定性。对Ellis-Jaffe求和规则的目标质量效应也作了简要的讨论。

$1/N_c$对$g_A$的转动修正和核子的等矢量磁矩

$1/N_c$ Rotational Corrections to $g_A$ and Isovector Magnetic Moment of the Nucleon

在Nambu-Jona-Lasinio模型下，研究了$1/N_c$对核子轴向矢量常数和等矢量磁矩的转动修正.我们遵循半经典量子化过程中的路径积分，其中我们可以包括微扰的角速度$Ω\sim \frac 1{N_c}$的权力的修正。我们发现非零的$1/N_c$阶修正的价和狄拉克海夸克。这些修正值足够大，可以解决长期存在的问题，即在主序中对$g_A$和$μ^{IV}$的严重低估。轴向常数$g_A$被很好地再现，而等矢量磁矩$μ^{IV}$仍然被低估了25%。

核子自旋结构函数$G_2(x,Q^2)$的修正

QCD Corrections to the nucleon's spin structure function $G_2(x,Q^2)$

我们研究了与自旋相关结构函数$g_{2}(x, Q^{2})$相关的扭曲3算符的重整化。我们通过计算扭曲3算符的离壳格林函数，包括与运动方程成比例的算符，导出了非单态部分的反常维数。

孤立子SU（3）-NJL模型中核子在$1/N_c$修正下的轴向性质

Axial Properties of the Nucleon with $1/N_c$-Corrections in the solitonic SU(3)-NJL-Model

在半玻色化SU（3）-NJL模型中，计算了重子的质量分裂和核子的轴向矢量耦合常数。如果考虑$m_s$中的二阶修正，超子的质量分裂可以很精确地再现。新的修正来自子领导项的轴向矢量电流的$1/N_c$膨胀被证明是非零的，并大大提高了轴向量的唯象预测。最后给出了$g_{\rm A}$的数值，分别是$g_A^{(0)}=0.37$、$g_A^{(3)}=1.38$和$g_A^{(8)}=0.31$，它们较好地再现了轻子散射的最新数据。

Deeply virtual electroproduction of photons and mesons on the nucleon : leading order amplitudes and power corrections

We estimate the leading order amplitudes for exclusive photon and meson electroproduction reactions at large Q^2 in the valence region in terms of skewed quark distributions. As experimental investigations can currently only be envisaged at moderate values of Q^2, we estimate power corrections due to the intrinsic transverse momentum of the partons in the meson wavefunction and in the nucleon. To this aim the skewed parton distribution formalism is generalized so as to include the parton intrinsic transverse momentum dependence. Furthermore, for the meson electroproduction reactions, we calcul…

Nucleon QCD sum rules with the radiative corrections

QCD sum rules for the nucleon are considered in complex q^2 plane with inclusion of the radiative corrections of the order alpha_s. It is shown that the radiative corrections affect mainly the residue lambda^2 of the nucleon pole. Their influence on the value of the nucleon mass is much smaller. Following the ideas of Ioffe and Zyablyuk we expand the analysis to complex values of q^2. This provides a more stable solution. Varying the weights of the contributions of different dimensions by changing the value of the angle in the complex plane we find the value of the six-quark condensate which i…

The Impact of NLO-Corrections on the Determination of the $\bar{u},\bar{d} Content of Nucleons from Drell-Yan Production

The interpretation of Drell-Yan production in terms of the antiquark densities depends on NLO corrections. Besides the NLO corrections to the familiar annihilation $q\bar{q}\to γ^* \to l^+ l^-$, there is a substantial contribution from the QCD Compton subprocesses $gq \to qγ^* \to q l^+ l^-$ and $g\bar{q} \to qγ^* \to q l^+ l^-$. The beam and target dependence of the two classes of corrections is different. We discuss the impact of this difference on the determination of the $\bar{d}-\bar{u}$ asymmetry in the proton from the comparison of the $pp$ and $pn$ Drell-Yan production.

Matrix Model for the Transition Expansion of Dispersive Corrections to Nucleon-Nucleus Total Cross Sections

A finite-dimensional matrix model for the nucleon-nucleon cross section operator is used to calculate the dispersive correction to nucleon-nucleus total cross sections, and the leading terms in its expansion in the number of inelastic transitions in the high-energy limit where the longitudnal momentum transfers can be ignored.

Heavy boson production through the collision of an ultrahigh-energy neutrino on a target nucleon

We discuss W and Z production through the deep inelastic neutrino-nucleon scattering in the context of the standard model SU(3)x SU(2)x U(1) of the strong and electroweak interactions. We find the cross section rates for the process neutrino + nucleon --> lepton(-) + W(+) + X for the case of ultrahigh-energy neutrinos colliding on a target nucleon.

Bremsstrahlung in weak charged current polarized lepton-nucleon deep inelastic scattering

The processes of lepton-nucleon scattering, including ones with both polarized beams, at high energy provide relevant information about interaction and particles structure, allowing to analyze nucleon spin structure. As energy and experimental accuracy rise, necessity to improve Born cross sections and polarized asymmetries with higher order radiative corrections becomes substantial. In this report we stress on lowest order bremsstrahlung corrections treatment using helicity amplitudes method as applied to actual nowadays charged current lepton-nucleon deep inelastic processes, that allows to …

Subleading contributions to the chiral three-nucleon force II: Short-range terms and relativistic corrections

We derive the short-range contributions and the leading relativistic corrections to the three-nucleon force at next-to-next-to-next-to-leading order in the chiral expansion.

The nucleon's octet axial-charge g_A^8 with chiral corrections

The value of the nucleon's flavour-singlet axial-charge extracted from polarised deep inelastic scattering is sensitive to the value of the octet axial-charge g_A^8 which is usually taken from an analysis of hyperon beta-decays within the framework of SU(3) symmetry, namely 0.58 \pm 0.03. Using the Cloudy Bag model we find that the value of g_A^8 is reduced by as much as 20% below the usual phenomenological value. This increases the value of the flavour singlet axial charge (g_A^0|_inv) derived from deep inelastic data and significantly reduces the difference between it and g_A^8.

New Predictions for Electroweak O(α) Corrections to Neutrino--Nucleon Scattering

We calculate the O(α) electroweak corrections to charged- and neutral-current deep-inelastic neutrino scattering off an isoscalar target. The full one-loop-corrected cross sections, including hard photonic corrections, are evaluated and compared to an earlier result which is the basis of the NuTeV analysis. In particular, we compare results that differ in input-parameter scheme, treatment of real photon radiation and factorization scheme. The associated shifts in the theoretical prediction for the ratio of neutral- and charged-current cross sections can be larger than the experimental accuracy…

Finite volume corrections to the electromagnetic current of the nucleon

We compute corrections to both the isovector anomalous magnetic moment and the isovector electromagnetic current of the nucleon to $O(p^3)$ in the framework of covariant two-flavor Baryon Chiral Perturbation Theory. We then apply these corrections to lattice data for the anomalous magnetic moment from the LHPC, RBC & UKQCD and QCDSF collaborations.

Radiative Corrections to the Neutron Beta-decay within the Standard Model

Starting with the basic Lagrangian of the Standard Model, the radiative corrections to the neutron beta-decay are acquired. The electroweak interactions are consistently taken into consideration amenably to the Weinberg-Salam theory. The effect of the strong quark-quark interactions on the neutron beta-decay is parameterized by introducing the nucleon electromagnetic form factors and the nucleon weak transition current specified by the form factors g_V, g_A, ... The radiative corrections to the total decay probability W and to the asymmetry coefficient of the electron momentum distribution A o…

Next-to-Leading Order Corrections to Heavy Flavour Production in Longitudinally Polarized Photon-Nucleon Collisions

A complete next-to-leading order calculation of longitudinally polarized heavy quark photoproduction is presented. All results of the purturbative calculation are given in detail. For reactions and energies of interest cross sections differential in the transverse momentum and rapidity of the heavy quark, total cross sections and the corresponding asymmetries are given. Errors in the asymmetries are estimated and the possibility to distinguish between various scerarios of the polarized gluon distribution is discussed. Our results are compared with other related publications.

大爆炸核合成过程中核子质量对$p \leftrightarrow n$速率的修正

Nucleon Mass Corrections to the $p \leftrightarrow n$ Rates During Big Bang Nucleosynthesis

中子转换为质子的热速率，反之亦然，计算，包括1兆电子伏的顺序除以核子质量的校正。结果表明，大爆炸核合成中预言的原初氦丰度被系统地低估了约$δY_4 = 0.0012$，即，$δY_4 / Y_4 \approx .005$。

Nucleon spin structure functions at NNLO in the presence of target mass corrections and higher twist effects

We extract polarized parton distribution functions (PPDFs), referred to as "KTA17," together with the highly correlated strong coupling $α_s$ from recent and up-to-date $g_1$ and $g_2$ polarized structure functions world data at next-to-next-to-leading order in perturbative QCD. The stability and reliability of the results are ensured by including nonperturbative target mass corrections as well as higher-twist terms which are particularly important at the large-$x$ region at low Q$^2$. Their role in extracting the PPDFs in the nucleon is studied. Sum rules are discussed and compared with other…

QCD Corrections to Neutralino-Nucleon Scattering

We calculate the dominant loop corrections from both standard and supersymmetric QCD to the effective coupling of neutralinos to nucleons. The potentially largest corrections come from gluino-squark loop contributions to the Higgs boson couplings to quarks; these corrections also affect the leading spin-independent squark exchange contribution. Ordinary QCD corrections to the effective coupling of CP-even Higgs bosons to two gluons are also sizable. For large $\tanb$ values, i.e. in the region of parameter space probed by current and near-future direct Dark-Matter search experiments, the total…

NLO light-cone sum rules for the nucleon electromagnetic form factors

We study the electromagnetic nucleon form factors within the approach based on light-cone sum rules. We include the next-to-leading-order corrections for the contributions of twist-three and twist-four operators and a consistent treatment of the nucleon mass corrections in our calculation. It turns out that a self-consistent picture arises when the three valence quarks carry $40\%:30\%:30\%$ of the proton momentum.

Higher-twist corrections to nucleon structure functions from lattice QCD

A genuinely non-perturbative evaluation of higher-twist contributions to the structure functions of the nucleon, with all mixing effects and renormalon ambiguities taken care of, is presented. Higher-twist corrections turn out to be significant at moderate values of $q^2$.

Nucleon form factors and final state radiative corrections to $e^+e^-\to \bar p p γ$

New parametrisation for the electric and the magnetic form factors of proton and neutron are presented. The proton form factors describe well the recent measurements by BaBar collaboration and earlier ones of the ratio of the form factors in space-like region. The neutron form factors are consistent with earlier measurements of neutron pair production and ratio of the form factors in the space-like region. These form factors are implemented into the generator PHOKHARA, which simulates the reactions $e^+e^-\to \bar p p γ$ and $e^+e^-\to \bar n nγ$. The influence of final state radiation is inve…

组分夸克模型中核子形状因子的同位旋破缺修正

Isospin breaking corrections to nucleon form factors in the constituent quark model

在非相对论组分夸克模型中，研究了由于夸克质量差和夸克间库仑相互作用引起的核子波函数中的同位旋破缺及其对核子电弱形状因子的影响.该模型精确地计算了核子波函数和电弱形状因子中的机械诱导同位旋破缺。本文用一级微扰理论计算了电磁诱导的同位旋混合物，包括最低共振态和核子量子数，但同位旋为3/2。我们发现一个小的（$\leq 1\%$），但有限的修正异常的磁矩的核子几乎完全源于夸克质量差，而静态核子轴向耦合仍然是未修正的。核子的电荷半径、磁性半径和轴向半径都出现了相同数量级的修正。在这个模型中对电荷半径的修正基本上是等截面的，并且对于从例如违反电子-质子不对称性的弹性前向角宇称或弹性${}^4He({\vec e},e')$实验中提取奇异性半径可能具有一定的意义。

$σ_{DIS}(νN)$, NLO Perturbative QCD and O(1 GeV) Mass Corrections

The deep-inelastic neutrino-nucleon cross section is one of the components of few GeV neutrino interactions. We present here our results for neutrino-isoscalar nucleon charged current scattering including perturbative next-to-leading order QCD corrections, target mass corrections, charm mass and lepton mass corrections.

Polarized lepton-nucleon scattering in frame of various guage model

The cross section for deep inelastic lepton-nucleon scattering with arbitrary polarized scattering fermions is calculated within the electroweak Standard Model and non-minimal gauge models with additional neutral boson. The Lorentz-invariant formulas for cross section and all types of electroweak asymmetries, polarized, charge-polarized, charged, including the first-order electroweak radiative correction are obtained. We present a detailed numerical discussion of the radiative corrections to different kinds of electroweak asymmetries. The difference in the results obtained in frame of minimal …

结构函数和核子有效质量的QCD分析

The QCD Analysis of the Structure Functions and Effective Nucleon Mass

基于轻子深度非弹性散射结构函数的靶质量修正，我们计算了核子的有效质量，结果表明核子在核靶上的深度非弹性散射的有效质量是$M_{nucl.}$的2倍，在氢靶上的有效质量是$M_{nucl.}$.

Nucleon Form Factors to Next-to-Leading Order with Light-Cone Sum Rules

We have calculated the leading-twist next-to-leading order (NLO), i.e., O(alpha_s), correction to the light-cone sum-rules prediction for the electromagnetic form factors of the nucleon. We have used the Ioffe nucleon interpolation current and worked in M_N=0 approximation, with M_N being the mass of the nucleon. In this approximation, only the Pauli form factor F_2 receives a correction and the calculated correction is quite sizable (cca 60%). The numerical results for the proton form factors show the improved agreement with the experimental data. We also discuss the problems encountered when…

Isospin-breaking corrections to the pion-nucleon scattering lengths

We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory. The so-called triangle relation is found to be violated by about 1.5 %. We encounter a substantial isospin-breaking correction to neutral-pion-nucleon scattering beyond Weinberg's prediction due to a cusp effect. Finally, the application to hadronic atoms is briefly discussed.

On chiral corrections to nucleon GPD

Within the pion-nucleon chiral perturbation theory we derive the leading chiral correction to the nucleon GPD at $ξ=0$. We discuss the difficulties of consideration of nonlocal light-cone operators within the theory with a heavy particle and the methods to solve the difficulties. The consideration of the chiral corrections directly for nonlocal operators allows to resolve the ambiguity of the inverse Mellin transformation. In particular, we show that the mixing between axial and vector GPDs are of order $m_π^2/M_N^2$, which is two orders of magnitude less that it follows from the Mellin moment…

Leading Chiral Corrections to the Nucleon Generalized Parton Distributions

Using heavy baryon chiral perturbation theory we study the leading chiral corrections to the complete set of nucleon generalized parton distributions (GPDs). We compute the leading quark mass and momentum transfer dependence of the moments of nucleon GPDs through the nucleon off-forward twist-2 matrix elements. These results are then applied to get insight on the GPDs and their impact parameter space distributions.

Radiative Corrections to Neutrino-Nucleon Quasielastic Scattering

Full one-loop radiative corrections are calculated for low energy neutrino-nucleon quasi-elastic scattering, $\bar ν_{e}+p \longrightarrow e^{+} + n$, which involves both Fermi and Gamow-Teller transitions, in the static limit of nucleons. The calculation is performed for both angular independent and dependent parts. We separate the corrections into the outer and inner parts {\` a} la Sirlin. The outer part is infrared and ultraviolet finite, and involves the positron velocity. The calculation of the outer part is straightforward, but that of the inner part requires a scrutiny concerning the c…

New experimental constraints on polarizability corrections to hydrogen hyperfine structure

We present a state-of-the-art evaluation of the polarizability corrections--the inelastic nucleon corrections--to the hydrogen ground-state hyperfine splitting using analytic fits to the most recent data. We find a value $Δ_{\rm pol} = 1.3 \pm 0.3$ ppm. This is 1--2 ppm smaller than the value of $Δ_{\rm pol}$ deduced using hyperfine splitting data and elastic nucleon corrections obtained from modern form factor fits.

Electromagnetic Corrections to Low-Energy pi-pi Scattering

Electromagnetic corrections to the low-energy pi+ pi- -> pi0 pi0 scattering amplitude at next-to-leading order in the chiral expansion are reviewed. Their effects on the corresponding scattering lengths are estimated and compared to the two-loop strong interaction contributions. Contribution to the proceedings of the Eighth International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon, Zuoz, Engadine, Switzerland, August 15-21 1999.

The Physics Case for Polarised Proton-Nucleon Scattering at HERA

The physics case for a possible fixed target polarized nucleon-nucleon collision experiment at HERA is described. The experiment named HERA-N could be realized using an internal polarized gas target in the HERA polarized/unpolarized proton beam. A wide spectrum of nucleon spin structure problems could be investigated and the experiment would constitute a fixed target complement to the RHIC spin physics program with competitive statistical accuracy.

Triple-Pomeron Matrix Model for Dispersive Corrections to Nucleon-Nucleus Total Cross Section

Dispersive corrections to the total cross section for high-energy scattering from a heavy nucleus are calculated using a matrix model, based on the triple-Pomeron behavior of diffractive scattering from a single nucleon, for the cross section operator connecting different states of the projectile nucleon . Energy-dependent effects due to the decrease in longitudinal momentum transfers and the opening of more channels with increasing energy are included. The three leading terms in an expansion in the number of inelastic transitions are evaluated and compared to exact results for the model in th…

QCD and power corrections to sum rules in deep-inelastic lepton-nucleon scattering

In this paper we study QCD and power corrections to sum rules which show up in deep inelastic lepton-hadron scattering. Furthermore we will make a distinction between fundamental sum rules which can be derived from quantum field theory and those which are of a phenomenological origin. Using current algebra techniques the fundamental sum rules can be expressed into expectation values of (partially) conserved (axial-) vector currents sandwiched between hadronic states. These expectation values yield the quantum numbers of the corresponding hadron which are determined by the underlying flavour gr…

2-Nucleon 1-Loop Corrections to Pion Double Charge Exchange within Heavy Baryon Chiral Perturbation Theory

One-loop corrections at the two-nucleon level to Pion Double Charge exchange (DCX) scattering off a nuclear target at threshold, are calculated within the framework of Heavy Baryon Chiral Perturbation Theory (HBChPT). An estimate for the (2-nucleon) 1-loop correction is obtained in the static limit and using an impulse approximation. We find a small (1.6%) increase relative to the leading order tree graphs.

Fixed poles, polarized glue and nucleon spin structure

We review the theory and present status of the proton spin problem with emphasis on possible gluonic and sea contributions. We discuss the possibility of a J=1 fixed pole correction to the Ellis-Jaffe sum rule for polarized deep inelastic scattering. Fixed poles in the real part of the forward Compton scattering amplitude have the potential to induce subtraction constant corrections to sum rules for photon nucleon scattering.

Nuclear Corrections for Cross Section of Lepton Inelastic Scattering

Main nuclear corrections for inelastic scattering of charged leptons on nuclei, namely shadowing, EMC-effect and Fermi motion have been investigated. Simple formulas describing these effects for different x-regions have been proposed, and unified expression for any transferred energy and momentum as well as for different nuclei has been obtained. Results of calculations of the ratio of nucleus structure function (per nucleon) and free nucleon structure function are in a good agreement with SLAC data.

束缚核子的离壳效应与来自$^1$H、$^2$H、$^3$H和$^3$He数据的部分子分布函数

Off-shell effects in bound nucleons and parton distributions from $^1$H, $^2$H, $^3$H and $^3$He data

本研究开展含多种轻核靶标深度非弹性散射数据的全球QCD分析，用核卷积方法处理核修正，全局拟合约束离壳修正、质子部分子分布函数与高扭度项，验证了质子与中子的相对离壳修正相等，为核子结构研究提供新约束。

OPE analysis of the nucleon scattering tensor including weak interaction and finite mass effects

We perform a systematic operator product expansion of the most general form of the nucleon scattering tensor $W_{μν}$ including electro-magnetic and weak interaction processes. Finite quark masses are taken into account and a number of higher-twist corrections are included. In this way we derive relations between the lowest moments of all 14 structure functions and matrix elements of local operators. Besides reproducing well-known results, new sum rules for parity-violating polarized structure functions and new mass correction terms are obtained.

质子诱导Drell-Yan产生中核子的海夸克含量

Sea-quark Content of Nucleons from Proton-induced Drell-Yan Production

我们分析了质子诱导的Drell-Yan生产的味道不对称性和违反Gottfried总和规则的同位旋断裂的解释。从三种不同形式的修正味和同位旋对称部分子分布的后果进行检查。计算结果对参数和部分子分布的选择以及修正的引入方式很敏感。所有三种形式的修正都可以与最近的费米实验室E772数据相一致的截面比$R=σ_{W}/σ_{IS}$和$^{2}$ H的微分截面$m^{3}d^{2}σ/dx_{F}dm$的形状。

Electroweak radiative corrections to neutrino--nucleon scattering at NuTeV

A dedicated effort by both the experimental and theoretical communities is crucial for achieving a precise determination of Standard Model parameters such as the $W$ mass ($M_W$). $M_W$ is measured directly at the CERN LEP2 $e^+ e^-$ and the Fermilab Tevatron $p \bar p$ colliders, resulting in a precision of $δM_W/M_W=0.03%$. A complementary $M_W$ measurement is provided by the NuTeV collaboration, who extract $\sin^2 θ_W$, and thus $M_W$, from the ratio of deep-inelastic neutral and charged-current neutrino(anti-neutrino)-Nucleon ($νN(\bar νN)$) scattering cross sections. However, their resul…

Transverse Target Single Spin Asymmetry in Elastic e-{\p} Scattering

Using the Coulomb Eikonal Phase associated with a transversely polarized nucleon, we calculate the azimuthal single spin asymmetry of unpolarized electrons elastically scattered from a transversely polarized nucleon target. The azimuthal asymmetry in this case is attributed to the fact that in a transversely polarized nucleon, the transverse charge density is no longer axially symmetric and is distorted due to the transverse spin of the nucleon. This asymmetry in the nucleon charge density causes a left-right asymmetry in the azimuthal distribution of the scattered electrons. In our approach, …

Target-mass corrections and the Bloom-Gilman duality of the nucleon structure function

The occurrence of the Bloom-Gilman local duality in the low-order moments of the nucleon structure function is investigated for values of the squared four-momentum transfer Q**2 between ~ 0.5 and 10 (GeV/c)**2. At variance with previous analyses truncated Cornwall-Norton moments, limited to the nucleon-resonance production regions, are considered. The role played by target-mass corrections is illustrated, showing that target-mass effects are necessary (but not sufficient) for producing the observed Bloom-Gilman duality of the nucleon structure function. The possibility of a local duality betwe…

Study of Two-Photon Corrections in the $p\bar{p} --> e+e-$ Process: Hard Rescattering Mechanism

We investigate the two-photon corrections to the process $p\bar{p} \to e^+e^-$ at large momentum transfer, aimed to access the time-like nucleon form factors. We estimate the two-photon corrections using a hard rescattering mechanism, which has already been used to calculate the corresponding corrections to elastic electron-proton scattering. Using different nucleon distribution amplitudes, we find that the two-photon corrections to the $p\bar{p} \to e^+e^-$ cross sections in the momentum transfer range 5 - 30 GeV$^2$ is below the 1 % level.

Production of W-+ with an anomalous magnetic moment via the collision of an ultrahigh-energy (anti)neutrino on a target nucleon

We discuss the production of W-+ bosons in deep inelastic processes (anti-nu)nu + nucleon --> l+- + W-+ + X, in the context of an electroweak model in which the vector boson self interactions may be different from those prescribed by the electroweak standard model. We present results which show the strong dependence of the cross section on the anomalous magnetic dipole moment kappa of the W+-. We show that even small deviations from the standard model value of kappa (kappa=1) could imply large deviations in the cross section rates of W-+ production through the collision of an ultrahigh energy …

NNLO Corrections to Nucleon-Nucleon Scattering and Perturbative Pions

The 1S0, 3S1, and 3D1 nucleon-nucleon scattering phase shifts are calculated at next-to-next-to-leading order (NNLO) in an effective field theory. Predictions for the 1P1, 3P0, 3P1, 3P2, 1D2, 3D2, and 3D3 phase shifts at this order are also compared with data. The calculations treat pions perturbatively and include the NNLO contributions from order $Q_r^3$ and $Q_r^4$ radiation pion graphs. In the 3S1, 3D1, 3P0, and 3P2 channels we find large disagreement with the Nijmegen partial wave analysis at NNLO. These spin triplet channels have large corrections from graphs with two potential pion exch…