Mon·Oct 5, 2015Monday·October 5, 2015

1. 01*

   Discrete symmetries and mixing of Dirac neutrinos

   Arman Esmaili🇮🇹 · Alexei Yu. Smirnov🇩🇪

   We study mixing of the Dirac neutrinos in the residual symmetries approach. The key difference from the Majorana case is that the Dirac mass matrix may have larger symmetries: $G_{\nu }={\mathbf{Z}}_n$ with $n\ge 3$. The symmetry group relations have been generalized to the case of Dirac neutrinos. Using them we have found all new relations between mixing parameters and corresponding symmetry assignments which are in agreement with the present data. The viable relations exist only for the charged lepton residual symmetry $G_{\ell }={\mathbf{Z}}_2$. The relations involve elements of the rows of the PMNS matrix and lead to precise predictions of the 2-3 mixing angle and certain ranges of the CP violation phase. For larger symmetries $G_{\ell }$, an agreement with data can be achieved if $\sim 10\%$ corrections related to breaking of $G_{\ell }$ and $G_{\nu }$ are included.

   hep-phhep-exPRD(2015)·13 citations
2. 02*

   Low-derivative operators of the Standard Model effective field theory via Hilbert series methods

   Landon Lehman🇺🇸 · Adam Martin🇺🇸

   In this work, we explore an extension of Hilbert series techniques to count operators that include derivatives. For sufficiently low-derivative operators, we find an algorithm that gives the number of invariant operators, properly accounting for redundancies due to the equations of motion and integration by parts. Specifically, the technique can be applied whenever there is only one Lorentz invariant for a given partitioning of derivatives among the fields. At higher numbers of derivatives, equation of motion redundancies can be removed, but the increased number of Lorentz contractions spoils the subtraction of integration by parts redundancies. While restricted, this technique is sufficient to automatically generate the complete set of invariant operators of the Standard Model effective field theory for dimensions 6 and 7 (for arbitrary numbers of flavors). At dimension 8, the algorithm does not automatically generate the complete operator set; however, it suffices for all but five classes of operators. For these remaining classes, there is a well defined procedure to manually determine the number of invariants. Using these methods, we thereby derive the set of 535 dimension-8 $N_f=1$ operators.

   hep-phhep-thJHEP(2016)·200 citations
3. 03*

   NLO+NLL squark and gluino production cross-sections with threshold-improved parton distributions

   Wim Beenakker🇳🇱 · Christoph Borschensky🇩🇪 · Michael Krämer🇩🇪 · Anna Kulesza🇩🇪 · Eric Laenen🇳🇱 · Simone Marzani🇺🇸 · Juan Rojo🇬🇧

   We present updated predictions for the cross-sections for pair production of squarks and gluinos at the LHC Run II. First of all, we update the calculations based on NLO+NLL partonic cross-sections by using the NNPDF3.0NLO global analysis. This study includes a full characterization of theoretical uncertainties from higher orders, PDFs and the strong coupling. Then, we explore the implications for this calculation of the recent NNPDF3.0 PDFs with NLO+NLL threshold resummation. We find that the shift in the results induced by the threshold-improved PDFs is within the total theory uncertainty band of the calculation based on NLO PDFs. However, we also observe that the central values of the cross-sections are modified both in a qualitative and a quantitative way, illustrating the relevance and impact of using threshold-improved PDFs together with resummed partonic cross-sections. The updated NLO+NLL cross-sections based on NNPDF3.0NLO are publicly available in the NLL-fast format, and should be an important ingredient for the interpretation of the searches for supersymmetric particles at Run II.

   hep-phhep-exEPJC(2016)·82 citations
4. 04*

   New Limits on the Dark Matter Lifetime from Dwarf Spheroidal Galaxies using Fermi-LAT

   Matthew G. Baring🇺🇸 · Tathagata Ghosh🇺🇸 · Farinaldo S. Queiroz🇩🇪 · Kuver Sinha🇺🇸

   Dwarf spheroidal galaxies (dSphs) are promising targets for the indirect detection of dark matter through gamma-ray emission due to their proximity, lack of astrophysical backgrounds and high dark matter density. They are often used to place restrictive bounds on the dark matter annihilation cross section. In this paper, we analyze six years of {\it Fermi}-LAT gamma-ray data from 19 dSphs that are satellites of the Milky Way, and derive from a stacked analysis of 15 dSphs, robust 95\% confidence level lower limits on the dark matter lifetime for several decay channels and dark matter masses between $\sim 1$GeV and $10$TeV. Our findings are based on a bin-by-bin maximum likelihood analysis treating the J-factor as a nuisance parameter using PASS 8 event-class. Our constraints from this ensemble are among the most stringent and solid in the literature, and competitive with existing ones coming from the extragalactic gamma-ray background, galaxy clusters, AMS-02 cosmic ray data, Super-K and ICECUBE neutrino data, while rather insensitive to systematic uncertainties. In particular, among gamma-ray searches, we improve existing limits for dark matter decaying into $\bar{b}b$, (${\mu }^{+}{\mu }^{-}$) for DM masses below $\sim 30(200)$~GeV, demonstrating that dSphs are compelling targets for constraining dark matter decay lifetimes.

   hep-phastro-ph.HEhep-exPRD(2016)·93 citations
5. 05*

   Matching next-to-leading order predictions to parton showers in supersymmetric QCD

   Celine Degrande🇬🇧 · Benjamin Fuks🇫🇷 · Valentin Hirschi🇺🇸 · Josselin Proudom🇫🇷 · Hua-Sheng Shao🇨🇭

   We present a fully automated framework based on the FeynRules and MadGraph5 aMC@NLO programs that allows for accurate simulations of supersymmetric QCD processes at the LHC. Starting directly from a model Lagrangian that features squark and gluino interactions, event generation is achieved at the next-to-leading order in QCD, matching short-distance events to parton showers and including the subsequent decay of the produced supersymmetric particles. As an application, we study the impact of higher-order corrections in gluino pair-production in a simplified benchmark scenario inspired by current gluino LHC searches.

   hep-phhep-exPLB(2016)·23 citations
6. 06*

   Radiative corrections to the Dalitz plot of K_{l3}^0 decays

   M. Neri🇲🇽 · A. Martinez🇲🇽 · C. Juarez-Leon🇲🇽 · J.J. Torres🇲🇽 · Ruben Flores-Mendieta🇲🇽

   A model-independent expression for the Dalitz plot of semileptonic decays of neutral kaons, K_{l3}^0, including radiative corrections to order (\alpha/\pi)(q/M_1), where q is the momentum transfer and M_1 is the mass of the kaon, is presented. The model dependence of radiative corrections is kept in a general form within this approximation, which is suitable for model-independent experimental analyses. Expressions for bremsstrahlung radiative corrections are presented in two forms: one with the triple integral over the kinematical variables of the photon ready to be performed numerically and the other one in a fully analytical form. The final result is restricted to the so-called three-body region of the Dalitz plot and it is not compromised to fixing the values of the form factors at predetermined values.

   hep-phPRD(2015)·9 citations
7. 07*

   Through precision straits to next standard model heights

   André David (1)🇨🇭 · Giampiero Passarino (2 and 3) ((1) PH Department, CERN, Geneva, Switzerland, (2) Dipartimento di Fisica Teorica, Università di Torino, Italy, (3) INFN, Sezione di Torino, Italy)🇮🇹

   After the LHC Run 1, the standard model (SM) of particle physics has been completed. Yet, despite its successes, the SM has shortcomings vis-à-vis cosmological and other observations. At the same time, while the LHC restarts for Run 2 at 13 TeV, there is presently a lack of direct evidence for new physics phenomena at the accelerator energy frontier. From this state of affairs arises the need for a consistent theoretical framework in which deviations from the SM predictions can be calculated and compared to precision measurements. Such a framework should be able to comprehensively make use of all measurements in all sectors of particle physics, including LHC Higgs measurements, past electroweak precision data, electric dipole moment, $g-2$, penguins and flavor physics, neutrino scattering, deep inelastic scattering, low-energy $e^{+}{e}^{-}$ scattering, mass measurements, and any search for physics beyond the SM. By simultaneously describing all existing measurements, this framework then becomes an intermediate step, pointing us toward the next SM, and hopefully revealing the underlying symmetries. We review the role that the standard model effective field theory (SMEFT) could play in this context, as a consistent, complete, and calculable generalization of the SM in the absence of light new physics. We discuss the relationship of the SMEFT with the existing kappa-framework for Higgs boson couplings characterization and the use of pseudo-observables, that insulate experimental results from refinements due to ever-improving calculations. The LHC context, as well as that of previous and future accelerators and experiments, is also addressed.

   hep-phhep-exRev.Phys.(2016)·42 citations
8. 08*

   Conditions for Statistical Determination of the Neutrino Mass Spectrum in Radiative Emission of Neutrino Pairs in Atoms

   Ningqiang Song🇺🇸 · R. Boyero Garcia🇪🇸 · J. J. Gomez-Cadenas🇪🇸 · M. C. Gonzalez-Garcia🇪🇸 · A. Peralta Conde🇪🇸 · Josep Taron🇪🇸

   The photon spectrum in macrocoherent atomic de-excitation via radiative emission of neutrino pairs (RENP) has been proposed as a sensitive probe of the neutrino mass spectrum, capable of competing with conventional neutrino experiments. In this paper we revisit this intriguing technique in order to quantify the requirements for statistical determination of some of the properties of the neutrino spectrum, in particular the neutrino mass scale and the mass ordering. Our results are sobering. We find that, even under ideal conditions, the determination of neutrino parameters needs experimental live times of the order of days to years for several laser frequencies, assuming a target of volume of order 100 cm3 containing about 10^21 atoms per cubic centimeter in a totally coherent state with maximum value of the electric field in the target. Such conditions seem to be, as of today, way beyond the reach of our current technology.

   hep-phhep-exPRD(2016)·21 citations
9. 09*

   Higher charmonia and bottomonia. Nature of the X(3872)

   J. Ferretti🇮🇹 · E. Santopinto🇮🇹 · H. García-Tecocoatzi🇲🇽

   In this contribution, we will discuss our unquenched quark model re- sults for the spectra of cc and bb states. The spectra are calculated in the unquenched quark model formalism, where the physical mass of a meson is the sum of a bare mass contribution plus a self-energy correc- tion, due to the coupling to the meson-meson continuum. We will also discuss the quark structure of the X(3872). Its open-flavor and radiative decays are calculated in the quark model formalism. In our interpreta- tion, the wave function of the X(3872) is the sum of two contributions, a cc core plus higher Fock components, due to meson-meson continuum components. Our results for the spectra, open-flavor and radiative decays are compared to the existing experimental data.

   hep-ph2 citations
10. 10*

    Massive Yang-Mills for Vector and Axial-Vector Spectral Functions at Finite Temperature

    Paul M. Hohler🇺🇸 · Ralf Rapp🇺🇸

    The hadronic mechanism which leads to chiral symmetry restoration is explored in the context of the rho-pi-a_1 system using Massive Yang-Mills, a hadronic effective theory which governs their microscopic interactions. In this approach, vector and axial-vector mesons are implemented as gauge bosons of a local chiral gauge group. We have previously shown that this model can describe the experimentally measured vector and axial-vector spectral functions in vacuum. Here, we carry the analysis to finite temperatures by evaluating medium effects in a pion gas and calculating thermal spectral functions. We find that the spectral peaks in both channels broaden along with a noticeable downward mass shift in the a_1 spectral peak and negligible movement of the rho peak. The approach toward spectral function degeneracy is accompanied by a reduction of chiral order parameters, i.e., the pion decay constant and scalar condensate. Our findings suggest a mechanism where the chiral mass splitting induced in vacuum is burned off. We explore this mechanism and identify future investigations which can further test it.

    hep-phnucl-thAnnals Phys.(2016)·18 citations
11. 11*

    Non-perturbative collisional energy loss of heavy quarks in quark-gluon plasma

    Nikolai Kochelev🇷🇺 · Hee-Jung Lee🇰🇷 · Yongseok Oh🇰🇷 · Baiyang Zhang🇨🇳 · Pengming Zhang🇨🇳

    We suggest a new mechanism for the energy loss of fast heavy quarks in quark-gluon plasma. This mechanism is based on pion production caused by the anomalous chromomagnetic quark-gluon-pion interaction induced by strong topological fluctuations of the gluon fields represented by instantons. We found that this mechanism gives a considerable contribution to the collisional energy loss of a heavy quark in quark-gluon plasma, which shows a nontrivial role of nonperturbative phenomena in strongly interacting quark-gluon plasma.

    hep-phhep-exnucl-exnucl-thPRC(2016)·5 citations
12. 12*

    Study of vacuum behavior for inert models with discrete $Z_2$-like and abelian $U(1)$ symmetries

    Andrés Castillo🇨🇴 · Rodolfo A. Diaz🇨🇴 · John Morales🇨🇴 · Carlos G. Tarazona🇨🇴

    We study the vacuum behavior at one loop level in extended Higgs sectors with two doublets (2HDM), where $U(1)$ and $Z_2$ symmetries are considered to protect the $CP$ symmetry in the Higgs potential and to avoid Flavor Changing Neutral Currents at tree level in the Yukawa sector. In the Inert Higgs Model case, a detailed comparison is made between both models by using the energy evolution of couplings, which should satisfy energy scale dependent relations deduced for minima and stationary points of the Higgs potential at tree level. Besides, perturbative unitarity constraints at tree level are considered to generate the allowed parameter space compatible with perturbativity (absence of Landau poles). Our studies illustrate exclusion regions for Higgs masses and other combinations of couplings in the scalar sector, in particular for splittings of mass square for neutral scalars $A^0$ and $H^0$, as well as the difference between the sum of these and the charged Higgs mass square. From the vacuum stability for inert-2HDM at the tree and one loop levels, analyses lead us to find out new hierarchical structures for scalar masses. To complete vacuum studies on the Inert model, and based on reparameterization invariance of the Higgs potential, we compute original discriminants that allow ensuring the presence of a global electroweak minimum at tree level. Moreover, the behavior in high energy scales drives out analyzing criticality phenomena for the additional parameters of extended Higgs sectors. Finally, and using the consistency with the electroweak precision analyses of oblique parameters, we describe several implications from different regimes of the inert model on charged and pseudoscalar Higgs searches.

    hep-ph4 citations
13. 13*

    Rare Semileptonic Charm Decays

    Stefan de Boer🇩🇪

    An analysis of charm mesons decaying semileptonically via Flavor Changing Neutral Currents is presented. We calculate the Wilson coefficients within the Standard Model. A window in the decay distribution, where physics beyond the Standard Model could be measured is identified. Exemplary, we study effects of leptoquark models.

    hep-ph2 citations
14. 14*

    The light-front energy-momentum tensor

    Cédric Lorcé (CPHT, Ecole Polytechnique)🇺🇸

    We present the first complete parametrization for the matrix elements of the generic light-front gauge-invariant energy-momentum tensor, derive the expressions giving separately the spin and orbital angular momentum of quarks and gluons as probed in high-energy scattering experiments, and discuss the relations with two-parton generalized and transverse-momentum dependent distributions. As a by-product, we recovered the Burkardt sum rule, clarified its physical meaning and obtained similar new sum rules for higher-twist distributions.

    hep-phnucl-thPoS(2015)·0 citations
15. 15*

    The thermal dilepton rate at NLO at small and large invariant mass

    Jacopo Ghiglieri🇨🇭

    We report on a recent next-to-leading order perturbative determination of the dilepton rate from a hot QCD plasma for frequency and momentum of the order of the temperature and for much smaller invariant mass $M\sim gT$. We briefly review the calculation, which generalizes the previous one for the photon case ($M=0$). We then analyze the consequences of the new calculation for the extraction of the photon rate from the small mass dilepton measurements. We then review a recent NLO determination at large $M$ and we show how to match and merge its results with the low-mass ones, resulting in a single rate which is NLO-accurate over the phenomenologically relevant region.

    hep-phNucl.Part.Phys.Proc.(2016)·6 citations
16. 16*

    A new version of the event generator Sibyll

    Felix Riehn🇩🇪 · Ralph Engel🇩🇪 · Anatoli Fedynitch🇩🇪 · Thomas K. Gaisser🇺🇸 · Todor Stanev🇺🇸

    The event generator Sibyll can be used for the simulation of hadronic multiparticle production up to the highest cosmic ray energies. It is optimized for providing an economic description of those aspects of the expected hadronic final states that are needed for the calculation of air showers and atmospheric lepton fluxes. New measurements from fixed target and collider experiments, in particular those at LHC, allow us to test the predictive power of the model version 2.1, which was released more than 10 years ago, and also to identify shortcomings. Based on a detailed comparison of the model predictions with the new data we revisit model assumptions and approximations to obtain an improved version of the interaction model. In addition a phenomenological model for the production of charm particles is implemented as needed for the calculation of prompt lepton fluxes in the energy range of the astrophysical neutrinos recently discovered by IceCube. After giving an overview of the new ideas implemented in Sibyll and discussing how they lead to an improved description of accelerator data, predictions for air showers and atmospheric lepton fluxes are presented.

    hep-phPoS(2016)·205 citations
17. 17*

    Drell-Yan phenomenology in the color dipole picture revisited

    Eduardo Basso🇧🇷 · Victor P. Goncalves🇧🇷 · Jan Nemchik🇸🇰 · Roman Pasechnik🇸🇪 · Michal Sumbera🇨🇿

    An extensive phenomenological study of the Drell-Yan (DY) process in $pp$ collisions at various energies is performed in the color dipole framework. Besides previously studied ${\gamma }^{\ast }$ production we have also included the $Z^0$ contribution relevant at large dilepton invariant masses. We investigate the DY cross section differential in invariant mass, rapidity and transverse momentum of the dilepton pair in $pp$ collisions at RHIC and LHC. We consider three different phenomenological models for the dipole cross section and found a reasonable agreement with the available data. As a further test of the color dipole formalism, we also study the correlation function in azimuthal angle between the dilepton pair and a forward pion $\Delta \varphi$ for different energies, dilepton rapidites and invariant masses. The characteristic double-peak structure of the correlation function around $\Delta \varphi \simeq \pi$ found for very forward pions and low-mass dilepton pairs is sensitive to the saturation effects and can be tested by future DY measurements in $pp$ collisions.

    hep-phPRD(2016)·33 citations
18. 18*

    From controversy to precision on the sigma meson: a review on the status of the non-ordinary $f_0(500)$ resonance

    J.R. Pelaez (universidad Complutense de Madrid)🇪🇸

    The existence and properties of the sigma meson have been controversial for almost six decades, despite playing a central role in the spontaneous chiral symmetry of QCD or in the nucleon-nucleon attraction. This controversy has also been fed by the strong indications that it is not an ordinary quark-antiquark meson. Here we review both the recent and old experimental data and the model independent dispersive formalisms which have provided precise determinations of its mass and width, finally settling the controversy and leading to its new name: $f_0(500)$. We then provide a rather conservative average of the most recent and advanced dispersive determinations of its pole position $\sqrt{s_{\sigma }}=449_{-16}^{+22}-i(275\pm 12)$. In addition, after comprehensive introductions, we will review within the modern perspective of effective theories and dispersion theory, its relation to chiral symmetry, unitarization techniques, its quark mass dependence, popular models, as well as the recent strong evidence, obtained from the QCD $1/N_c$ expansion or Regge theory, for its non ordinary nature in terms of quarks and gluons.

    hep-phnucl-thPhys.Rept.(2016)·499 citations
19. 19*

    Observation of the new emission line at ~3.5 keV in X-ray spectra of galaxies and galaxy clusters

    Dmytro Iakubovskyi🇺🇦

    The detection of an unidentified emission line in X-ray spectra of cosmic objects would be a 'smoking gun' signature for particle physics beyond the Standard Model. More than a decade of its extensive searches results in several narrow faint emission lines reported at 3.5, 8.7, 9.4 and 10.1 keV. The most promising of them is the emission line at ~3.5 keV reported in spectra of several nearby galaxies and galaxy clusters. Here I summarize its up-to-date status, overview its possible interpretations, including an intriguing connection with radiatively decaying dark matter, and outline future directions for its studies.

    ↳ astro-ph.HEastro-ph.COhep-phAdv.Astron.Space Phys.(2016)·35 citations
20. 20*

    Aspects of moduli stabilization in type IIB string theory

    Shaaban Khalil🇪🇬 · Ahmad Moursy🇪🇬 · Ali Nassar🇪🇬

    We review moduli stabilization in type IIB string theory compactification with fluxes. We focus on the KKLT and Large Volume Scenario (LVS). We show that the predicted soft SUSY breaking terms in KKLT model are not phenomenological viable. In LVS, the following result for scalar mass, gaugino mass, and trilinear term is obtained: $m_0=m_{1/2}=-A_0=m_{3/2}$, which may account for Higgs mass limit if $m_{3/2}\sim \mathcal{O}(1.5)$ TeV. However, in this case the relic abundance of the lightest neutralino can not be consistent with the measured limits. We also study the cosmological consequences of moduli stabilization in both models. In particular, the associated inflation models such as racetrack inflation and Kähler inflation are analyzed. Finally the problem of moduli destabilization and the effect of string moduli backreaction on the inflation models are discussed.

    ↳ hep-thhep-phAdv.High Energy Phys.(2016)·1 citation
21. 21*

    Majorana Neutrino Magnetic Moment and Neutrino Decoupling in Big Bang Nucleosynthesis

    N. Vassh (Wisconsin U., Madison)🇺🇸 · E. Grohs ( Michigan U.)🇺🇸 · A.B. Balantekin (Wisconsin U., Madison)🇺🇸 · G.M. Fuller (UC, San Diego)🇺🇸

    We examine the physics of the early universe when Majorana neutrinos (electron neutrino, muon neutrino, tau neutrino) possess transition magnetic moments. These extra couplings beyond the usual weak interaction couplings alter the way neutrinos decouple from the plasma of electrons/positrons and photons. We calculate how transition magnetic moment couplings modify neutrino decoupling temperatures, and then use a full weak, strong, and electromagnetic reaction network to compute corresponding changes in Big Bang Nucleosynthesis abundance yields. We find that light element abundances and other cosmological parameters are sensitive to magnetic couplings on the order of 10^{-10} Bohr magnetons. Given the recent analysis of sub-MeV Borexino data which constrains Majorana moments to the order of 10^{-11} Bohr magnetons or less, we find that changes in cosmological parameters from magnetic contributions to neutrino decoupling temperatures are below the level of upcoming precision observations.

    ↳ astro-ph.COhep-phnucl-thPRD(2015)·31 citations
22. 22*

    Dilepton emission in high-energy heavy-ion collisions with dissipative hydrodynamics

    Gojko Vujanovic🇨🇦 · Gabriel S. Denicol🇨🇦 · Chun Shen🇨🇦 · Matthew Luzum🇨🇦 · Bjoern Schenke🇺🇸 · Sangyoung Jeon🇨🇦 · Charles Gale🇨🇦

    In this contribution we study the effects of three transport coefficients of dissipative hydrodynamics on thermal dilepton anisotropic flow observables. The first two transport coefficients investigated influence the overall size and growth rate of shear viscous pressure, while the last transport coefficient governs the magnitude of net baryon number diffusion in relativistic dissipative fluid dynamics. All calculations are done using state-of-the-art 3+1D hydrodynamical simulations. We show that thermal dileptons are sensitive probes of the transport coefficients of dissipative hydrodynamics.

    ↳ nucl-thhep-phnucl-ex3 citations
23. 23*

    Properties of hot and dense matter from relativistic heavy ion collisions

    Peter Braun-Munzinger🇩🇪 · Volker Koch🇺🇸 · Thomas Schaefer🇺🇸 · Johanna Stachel🇩🇪

    We review the progress achieved in extracting the properties of hot and dense matter from relativistic heavy ion collisions at the relativistic heavy ion collider (RHIC) at Brookhaven National Laboratory and the large hadron collider (LHC) at CERN. We focus on bulk properties of the medium, in particular the evidence for thermalization, aspects of the equation of state, transport properties, as well as fluctuations and correlations. We also discuss the in-medium properties of hadrons with light and heavy quarks, and measurements of dileptons and quarkonia. This review is dedicated to the memory of Gerald E. Brown.

    ↳ nucl-thhep-phnucl-exPhys.Rept.(2016)·385 citations
24. 24*

    A Future Polarized Drell-Yan Experiment at Fermilab

    David Kleinjan🇺🇸

    One of the great challenges of QCD is trying to understand the origin of the nucleon spin. Several decades of experimental measurements have shown that our current understanding is incomplete if only the quark and gluon spin contribution is considered. Over the last few years it has become increasingly clear that the contribution from the orbital angular momentum of the quarks and gluons has to be included as well. For instance, the sea quark orbital contribution remains largely unexplored. Measurements accessing the sea quark Sivers distribution will provide a probe of the sea quark orbital contribution. The upcoming E1039 experiment at Fermilab will access this distribution via the Drell-Yan process using a 120 GeV unpolarized proton beam directed on a polarized proton target. At E1039 kinematics the $u$-$\bar{u}$ annihilation process dominates the Drell-Yan cross section ($x_{Target}$ = 0.1 $\sim$ 0.35). If the $\bar{u}$ quark carries zero net angular momentum, then the measured Drell-Yan single-spin asymmetry should be zero, and vice versa. This experiment is a continuation of the currently running SeaQuest experiment.

    ↳ nucl-exhep-exhep-ph0 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.