638 research outputs found
Meson decay in an independent quark model
Leptonic decay widths and leptonic decay constants of light vector mesons and
weak leptonic decay widths and weak decay constants of light and heavy
pseudoscalar mesons have been studied in a field- theoretic framework based on
the independent quark model with a scalar- vector power-law potential. The
results are in very good agreement with the experimental data.Comment: 13 page
Partonske raspodjele u nukleonu na osnovi relativističkog modela neovisnih kvarkova
At a low resolution scale with Q2 = µ2 corresponding to the nucleon bound state, deep inelastic unpolarized structure functions F1(x, µ2) and F2(x, µ2) are derived, with correct support using the symmetric part of the hadronic tensor under some simplifying assumptions in the Bjorken limit. For doing this, the nucleon in its ground state has been represented by a suitably constructed momentum wave packet of its valence quarks in their appropriate SU(6) spin flavour configuration, with the momentum probability amplitude taken phenomenologically in reference to the independent quark model of scalar-vector harmonic potential. The valence quark distribution functions uv(x, µ2) and dv(x, µ2), extracted from the structure function F1(x, µ2) in a parton model interpretation, satisfy normalization constraints as well as the momentum sum-rule requirements at a bound state scale of µ2 = 0.1 GeV2. QCD evolution of these distribution functions taken as the inputs, yields at Q2 0 = 15 GeV2, xuv(x, Q2 0) and xdv(x, Q2 0) in good qualitative agreement with the experimental data. The gluon distribution G(x, Q2 0) and the sea-quark distribution qs(x, Q2 0), which are dynamically generated using the leading order renormalization group equation, also match reasonably well with the available experimental data.Upotrebom simetričnog dijela hadronskog tenzora, uz pojednostavljenje u Bjorkenovoj granici, izveli smo duboko-neelastične strukturne funkcije bez polarizacije F1(x, µ2) i F2(x, µ2) za slabo razlučivanje sa Q2 = µ2, što odgovara vezanom nukleonskom stanju. Nukleon se u svom osnovnom stanju predstavlja pogodno odabranim impulsnim valnim paketom svojih valentnih kvarkova u prikladnom SU(6) spinskom okusnom sklopu, a impulsne amplitude vjerojatnosti uzimaju se fenomenološki prema modelu neovisnih kvarkova skalarno-vektorskog harmoničkog potencijala. Iz strukturne funkcije F1(x, µ2) izvode se funkcije raspodjele valentnih kvarkova uv(x, µ2) i dv(x, µ2) u partonskom modelu, i one zadovoljavaju uvjete normalizacije i impulsnog zbrojnog pravila na ljestvici vezanja µ2 = 0.1 GeV2. Polazeći od tih funkcija za Q2 0 = 15 GeV2, QCD razvoj daje xuv(x, Q2 0) i xdv(x, Q2 0), u dobrom skladu s mjernim podacima. Gluonska G(x, Q2 0) i kvarkovska qs(x, Q2 0) raspodjela tvore se dinamički upotrebom jednadžbe renormalizacijske grupe u prvom redu i također se dobro slažu s mjernim podacima
Role of S gene product of bacteriophage lambda in host cell lysis
Studies with the induced lysogens of λ S +R+, λS-R+, λS+R- and λS-R- phages have shown that while the S gene product is essential for the action of intracellular R gene product to release the periplasmic alkaline phosphatase in the presence of EDTA, the latter gene product can bring about this effect while acting on Escherichia coli cells from outside, in the absence of functional S gene product; chloroform, could help the intracellular R gene product in effecting bacterial lysis in the absence of S gene product. These result support the premise that the S gene product facilitates the R gene product in crossing the cytoplasmic membrane into the periplasmic space such that the latter can act on the peptidoglycan layer of the host cell thus causing both the release of alkaline phosphatase and cell lysis
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