Search for evidence of two photon contribution in elastic electron proton data

We reanalyze the most recent data on elastic electron proton scattering. We look for a deviation from linearity of the Rosenbluth fit to the differential cross section, which would be the signature of the presence of two photon exchange. The two photon contribution is parametrized by a one parameter formula, based on symmetry arguments. The present data do not show evidence for such deviation.Comment: 15 pages 3 figures More details on the fitting procedure, more explicit explanation

K^- ^3He and K^+K^- interactions in the pd -> ^3He K^+K^- reaction

We investigate the K^- ^3He and K^+ K^- interactions in the reaction pd -> ^3He K^+ K^- near threshold and compare our model calculations with data from the MOMO experiment at COSY-Juelich. A large attractive effective K^- p amplitude would give a significant K^- ^3He final-state interaction effect which is not supported by the experimental data. We also estimate upper limits for the a_0(980) and f_0(980) contributions to the produced K^+ K^- pairs.Comment: 5 pages, 2 figures, accepted for publication in PR

The elastic electron-deuteron scattering beyond one-photon exchange

We discuss the elastic ed scattering beyond Born approximation. It is shown that the reaction amplitude contains six generalized form factors, but only three linearly independent combinations of them (we call them generalized charge, quadrupole and magnetic form factors) contribute to the reaction cross section in the second order perturbation theory. We examine two-photon exchange and find that it includes two types of diagrams, when two virtual photons interact with the same nucleon and when the photons interact with different nucleons. Estimations based on nonrelativistic calculations with the deuteron wave function for realistic NN potential show that the main contribution to the generalized charge, quadrupole and magnetic form factors comes from diagrams of the first type.Comment: v2, published version in PR

Polarization effects in the reaction e++e−→ρ++ρ−e^++e^-\to \rho^+ +\rho^- and determination of the ρ−\rho - meson form factors in the time--like region

The electron positron annihilation reaction into four pion production has been studied, through the channel $e^++e^-\to \bar \rho+\rho$. The differential (and total) cross sections and various polarization observables for this reaction have been calculated in terms of the electromagnetic form factors of the corresponding $\gamma^*\rho\rho$ current. The elements of the spin--density matrix of the $\rho -$meson were also calculated. Numerical estimations have been done, with the help of phenomenological form factors obtained in the space--like region of the momentum transfer squared and analytically extended to the time-like region.Comment: 19 pages, 2 figures, to appear in Phys Rev

Potassium Ions are More Effective than Sodium Ions in Salt Induced Peptide Formation

Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K(+) is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na(+), which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K(+) as the driving force, not Na(+), as commonly believed

Radiative corrections to polarization observables in elastic electron-deuteron scattering in leptonic variables

The model--independent QED radiative corrections to polarization observables in elastic scattering of unpolarized and longitudinally--polarized electron beam by the deuteron target have been calculated in leptonic variables. The experimental setup when the deuteron target is arbitrarily polarized is considered and the procedure for applying derived results to the vector or tensor polarization of the recoil deuteron is discussed. The basis of the calculations consists of the account for all essential Feynman diagrams which results in the form of the Drell-Yan representation for the cross-section and use of the covariant parametrization of the deuteron polarization state. The numerical estimates of the radiative corrections are given for the case when event selection allows the undetected particles (photons and electron-positron pairs) and the restriction on the lost invariant mass is used.Comment: 43 pages,3 figures. To be published in ZhTEF. revised 14.02.2012. arXiv admin note: text overlap with arXiv:nucl-ex/0002003 by other author

Cross section and polarization observables for the reaction e++e−→a1(1260)+πe^++e^-\to a_1(1260)+\pi

A model independent formalism for the electron positron annihilation reaction $e^++e^-\to a_1(1260)+\pi$ has been derived. The differential and total cross sections and the elements of the spin--density matrix of the $a_1$-meson were calculated in terms of the electromagnetic form factors of the corresponding $\gamma^*a_1\pi$ current. Simple models of $a_1$ form factors have been fitted to the available cross section data and they allow to give numerical predictions for the different observables.Comment: 19 pages, 6 figures Added formulas for axial meson decay in 3 pions Modified version to appear in PR

COMBINED ANTIHYPERTENSIVE THERAPY: ACE INHIBITOR PLUS CALCIUM CHANNEL BLOCKER. NEW ADVANTAGES OF THE KNOWN COMBINATION

Advantages of combined therapy of patients with arterial hypertension are considered. Special attention is paid to usage of ACE inhibitor and calcium antagonist combination

Undersøkelser av hydrokarboner og organiske miljøgifter i sedimenter fra Mareano-området i 2023

Havforskningsinstituttet har gjennomført målinger av hydrokarboner (PAH) i sedimenter fra 14 lokaliteter i Mareano-området, inkludert syv sedimentkjerner. I overflatesedimenter ble det i tillegg målt totalt hydrokarbon innhold (THC), bromerte flammehemmere (PBDE), klorerte miljøgifter (PCB og pesticider) og ved seks lokaliteter også «nye» organiske miljøgifter (PFAS, alkylfenoler, bisfenol A (BPA), dekloraner, fosfororganiske flammehemmere (PFR), klorparafiner og siloksaner). Prøvene var innsamlet i 2023 i områdene Sørlige Nordsjø 1 (NSJ-1) og Utsira i Nordsjøen og i deler av Skagerrak. Meget lave nivåer av hydrokarboner ble funnet i grove sedimenter fra område NSJ-1, mens noe høyere nivåer ble funnet i Utsira-område og enda høyere nivåer i Skagerrak. Benzo[a]pyren og PAH16 var i Miljødirektoratets klasse I («Bakgrunn») i område NSJ-1, klasse II («God tilstand») i Utsira-område og Skagerrak, og for PAH16 i tilstandsklasse III («Moderat forurenset») ved én lokalitet i Skagerrak. PAH-konsentrasjonsprofiler i kjernene tydet for det meste på tilførsler av pyrogene PAH i moderne sedimentlag, knyttet til antropogen påvirkning. Nivåene av menneskeskapte organiske miljøgifter av alle typer listet ovenfor var relativt lave eller meget lave. Nivåene var som regel høyere i Skagerrak enn i Nordsjøen. Nivåene tilsvarte Miljødirektoratets klasse II for de stoffene som det er etablert tilstandsklasser for, med unntaket av PFOS som var i tilstandsklasse III ved to lokaliteter i Skagerrak og Utsira-område, og BPA som var i denne klassen ved én lokalitet i Skagerrak.Undersøkelser av hydrokarboner og organiske miljøgifter i sedimenter fra Mareano-området i 2023publishedVersio