A model is suggested to interpret nucleon electromagnetic form factors both in space and time-like regions and to describe the existing data. It implies quarks to be colorless in the region of high ...intensity chromo-electromagnetic gluon field inside the nucleon.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK
Starting from the gauge invariant effective action in the quasi-multi-Regge kinematics (QMRK), we obtain the effective reggeized gluon (R)–particle (P) vertices of the following types:
R
P
P
,
R
R
P
...,
R
R
P
P
,
R
P
P
P
,
R
R
P
P
P
, and
R
P
P
P
P
, where the
on-mass-shell particles are gluons, or sets of gluons with small invariant masses. The explicit expressions satisfying the Bose-symmetry and gauge invariance conditions are obtained. As a comment to the Feynman rules for derivation of the amplitudes in terms of effective vertices we present a “vocabulary” for practitioners.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK
Oligotrophic bogs' runoff effect on surface waters Berezin, A E; Zakharova, E A; Parshina, N V ...
IOP conference series. Earth and environmental science,
11/2019, Volume:
400, Issue:
1
Journal Article
Peer reviewed
Open access
The removal of organic matter, including carbon, from oligotrophic bogs is determined by the amount of decomposed organic matter in bog waters and the runoff intensity. This process has a pronounced ...seasonal dynamics and is determined by weather conditions and characteristics of the bog runoff. The maximum watering is observed in the spring during snow thawing and in the autumn due to abundant precipitation and reduced evaporation. The amount of organic matter in bog water is determined by the air temperature of the previous period. Thus, the maximum carbon runoff from the bogs is possible in May-June and September, and the situation can vary considerably over the years, the weather being taken into account.
The process of electron–positron annihilation into proton–antiproton pair is considered within the vicinity of ψ(3770) resonance. The interference between the pure electromagnetic intermediate state ...and the ψ(3770) state is evaluated. It is shown that this interference is destructive and the relative phase between these two contributions is large (ϕ0≈250°).
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The known results of unitarity violation in QED are revised. Taking into account the peripheral processes in high energy ion collisions with production of an arbitrary number of pairs of charged ...leptons and pions, we confirm the known result of violation of unitarity in the frame of QED. Namely, the total cross section of production of an arbitrary number of pairs of charged particles grows more rapidly than any logarithmic power of the center-of-mass energy. The contribution from the production of a single neutral meson (scalar and pseudo-scalar) is discussed. An interpretation of this fact is expected to have a similar base to the known QED problem-the absence of the total cross section in the scattering of a charged particle on the Coulomb center. The relevant conditions cannot be realized in nature. The novelty of our calculations is in obtaining the explicit expression for differential cross sections of (in principle) any finite number of lepton and π+ π− pairs at peripheral hadron collisions. It can be measured at such facilities as RHIC or LHC.
The paper investigates contributions of
γ
,
Z
,
W
and ghost intermediate states of box-type to the parity-violating Møller scattering asymmetry up to two-loop level. Using the Yennie–Frautschi–Suura ...factorization form for amplitudes, we demonstrate that QED corrections, with an exception of vacuum-polarization effects, cancel at the asymmetry level. We obtain chiral amplitudes at Born, one-loop and partially at two-loop level: ladder boxes and decorated boxes. Our calculations are relevant for the ultra-precise 11 GeV MØLLER experiment planned at Jefferson Laboratory. The numerical comparison of the two-loop contributions with the experimental accuracy of MØLLER is provided.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We calculate the bilinear combination of Dirac tensors describing the creation of a pair of charged particles (pi-meson or leptons) by virtual photons integrated on the final particle phase volume. ...It can be interpreted as an s channel discontinuity of the zero angle light-by-light scattering tensor with both photons off-mass shell. The expression of the light-by-light scattering tensor is represented in the form where the gauge invariance and the Bose symmetry are explicitly shown. Some applications and the checks are discussed.
We show that the intermediate quarkonium state χc2(P23)(3556) in electron–positron annihilation to proton and antiproton as well as in antiproton–proton annihilation to electron and positron can give ...rise to backward–forward asymmetry. We apply the dispersion relation method, which allows us to express the asymmetry in terms of partial widths of quarkonium decay. The asymmetry dependence on the center of mass energy in the resonance region is presented. Quantitative comparison with similar effects induced in these reactions by QED effects and by the mechanism with neutral Z-boson in the intermediate state is given. We show that the asymmetry arising from the resonance excitation in the intermediate state is of the same order of the asymmetry of pure QED origin (∼10−2) which arises from the interference between initial and final state real photon emission.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, UL, UM, UPCLJ, UPUK
We consider an effective method for increasing the total efficiency of relativistic Cherenkov generators, viz., recuperation. It has been found that, for a generator with an efficiency smaller than ...15%, recuperation makes it possible to obtain an increase in the efficiency that exceeds 50% (from 12% to 68%). In generators with initially high efficiency (more than 50%), recuperation may turn out to be ineffective.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The production of pseudoscalar and scalar meson pairs ππ, ηη, η′η′, σσ as well as bound states in high energy γγ collisions are considered. The exchange by a vector particle in the binary process γ + ...γ → ha + hb with hadronic states ha, hb in fragmentation regions of the initial particle leads to nondecreasing cross sections with increasing energy, that is a priority of peripheral kinematics. Unlike the photon exchange the vector meson exchange needs a reggeization leading to fall with energy growth. Nevertheless, due to the peripheral kinematics beyond very forward production angles the vector meson exchanges dominate over all possible exchanges. The proposed approach allows one to express the matrix elements of the considered processes through impacting factors, which can be calculated in perturbation models like chiral perturbation theory (ChPT) or the Nambu-Jona-Lasinio (NJL) model. In particular cases the impact factors can be determined from relevant γγ sub-processes or the vector meson radiative decay width. The pionium atom production in the collisions of high energy electrons and pions with protons is considered and the relevant cross sections have been estimated.
PDF
