# HERMES

 2019-01-3012:31 [PUBDB-2019-00871] Journal Article/Contribution to a conference proceedings HERMES Collaboration Extraction of helicity amplitude ratios from exclusive $\rho^0$-meson electroproduction on transversely polarized protons XVII Workshop on High Energy Spin Physics, DSPIN-2017, DubnaDubna, Russia, 11 Sep 2017 - 15 Sep 2017   Exclusive $\rho^0$-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV$^2$ < Q$^2$ < 7.0 GeV$^2$, 3.0 GeV < W < 6.3 GeV, and -t' < 0.4 GeV$^2$. Using an unbinned maximum-likelihood method, 25 parameters are extracted. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2019-01-3012:18 [PUBDB-2019-00870] Journal Article/Contribution to a conference proceedings HERMES Collaboration Overview of recent HERMES results XVII Workshop on High Energy Spin Physics, DSPIN-2017, DubnaDubna, Russia, 11 Sep 2017 - 15 Sep 2017   An overview of more recent and important results from the HERMES experiment is presented in this paper. HERMES collected a wealth of data using the 27.6 GeV polarized HERA lepton beam and various polarized and unpolarized gaseous targets. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-12-3017:08 [PUBDB-2018-05932] Talk (non-conference) Rith, K. Some recent HERMES results COMPASS Meeting, CERNGeneva, CERN, Switzerland,   OpenAccess: PDF PDF (PDFA); 2018-12-3017:05 [PUBDB-2018-05930] Conference Presentation (Invited) Schnell, G. Measurements of transverse momentum distributions in semi-inclusive DIS Probing Nucleons and Nuclei in High Energy Collisions, Seattle, WASeattle, WA, United States, 1 Oct 2018 - 16 Nov 2018   OpenAccess: PDF; External link: Fulltext 2018-12-3017:00 [PUBDB-2018-05929] Conference Presentation HERMES Collaboration Medium Induced Modification of Negative Kaons Spectra in SIDIS Correlations in Partonic and Hadronic Interactions 2018, CPHI 2018, YerevanYerevan, Armenia, 24 Sep 2018 - 28 Sep 2018   OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-12-3016:55 [PUBDB-2018-05928] Conference Presentation (Invited) Schnell, G. Transverse-momentum distributions in electro-production and $e^+ e^-$ annihilation Correlations in Partonic and Hadronic Interactions 2018, CPHI 2018, YerevanYerevan, Armenia, 24 Sep 2018 - 28 Sep 2018   OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-12-3015:29 [PUBDB-2018-05922] Conference Presentation HERMES Collaboration Medium-induced modification of kaons spectra measured in SIDIS at HERMES XXIV International Baldin Seminar on High Energy Physics Problems, DubnaDubna, Russia, 17 Sep 2018 - 22 Sep 2018   The predicted high sensitivity of the nuclear modification factor for $K^-$ in SIDIS in respect to the medium-induced flavour conversion is studied at HERMES experiment. Unlike $\pi^+$, $\pi^-$ and $K^+$ nuclear modification factor for $K^-$ is assumed to increase at high value of Bjorken variable x and a hadron fraction energy z. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-12-3015:22 [PUBDB-2018-05920] Conference Presentation HERMES Collaboration Exclusive meson production at HERMES 23rd International Symposium on Spin Physics, Spin2018, FerraraFerrara, Italy, 10 Sep 2018 - 14 Sep 2018   Results from the study of exclusive $\rho^0$-meson electroproduction by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, are presented. In analysis of the angular dependence of the distribution of the decay pions, 25 parameters are extracted, which determine the real and imaginary parts of the ratios of several helicity amplitudes describing $\rho^0$-meson production by a virtual photon. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-12-3015:13 [PUBDB-2018-05919] Conference Presentation (Invited) Schnell, G. 30 years of HERMES - exploiting self-polarization in storage rings at HERA 23rd International Symposium on Spin Physics, Spin2018, FerraraFerrara, Italy, 10 Sep 2018 - 14 Sep 2018   Three decades ago it became that the simple quark model approach for the proton failed in describing the spin structure — the spin contribution from quarks, as measured by the European Muon Collaboration (EMC), came out small, by far insufficient to explain the proton spin of 1/2. The experiment utilized the polarized muon beam from CERN’s SPS, which is naturally polarized originating from the weak decay of mainly pions. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-12-3015:09 [PUBDB-2018-05918] Conference Presentation HERMES Collaboration The longitudinal double-spin asymmetries in semi-inclusive deep-inelastic scattering of electrons and positron by protons and deuterons 23rd International Symposium on Spin Physics, Spin2018, FerraraFerrara, Italy, 10 Sep 2018 - 14 Sep 2018 A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext