ترغب بنشر مسار تعليمي؟ اضغط هنا

Dilepton Production from Dropping rho in the Vector Manifestation

39   0   0.0 ( 0 )
 نشر من قبل Masayasu Harada
 تاريخ النشر 2008
  مجال البحث
والبحث باللغة English
 تأليف Masayasu Harada




اسأل ChatGPT حول البحث

In this write-up we summarize the main result of our analysis on the thermal dilepton production rate from the dropping rho based on the vector manifestation (VM). In the analysis, we showed that the effect of the strong violation of the vector dominance (VD) predicted by the VM, substantially suppresses the dilepton production rate compared with the one predicted by assuming the VD together with the dropping rho.

قيم البحث

اقرأ أيضاً

140 - G.Kulzinger 1998
We present a non-perturbative QCD calculation of high-energy diffractive photo- and leptoproduction of vector mesons $rho$, $rho$ and $rho$ on a nucleon. The initial photon splits up in a $qbar{q}$-dipole and transforms into a vector meson by scatter ing on the quark-diquark nucleon. The dipole-dipole scattering amplitude is provided by the non-perturbative model of the stochastic QCD vacuum, the wave functions result from considerations on the light-cone. We assume the physical $rho$- and $rho$-states to be mixed states of an active 2S-excitation and a rest whose coupling to the photon is suppressed. We obtain good agreement with the experimental data and get an understanding of the markedly different spectrum in the $pi^+pi^-$-invariant mass for photoproduction and $e^+e^-$-annihilation.
In a recent work from the ALICE collaboration an excess of relatively soft dilepton pairs was reported in p+p collisions at $13$ TeV. In the report no satisfactory explanation was found via standard bremsstrahlung computations. In this letter, textit {anomalous} dilepton pairs are produced non-perturbatively from the back-reaction of the vacuum to a $qbar{q}$ pair, travelling back-to-back. The dilepton spectrum is computed by folding this rate with the cross-section for the process p+p$rightarrow qbar{q}$, which was computed using the framework of the Color Glass Condensate Effective Field Theory (CGC EFT) in the $k_perp$-factorized limit. The resulting spectra is compatible within uncertainties with the data, and moreover, provides exciting insight into the non-perturbative phenomena that ultra-soft electromagnetic radiation can probe.
103 - G.Kulzinger 1999
In the framework of non-perturbative QCD we calculate high-energy diffractive production of vector mesons $rh, rh$ and $rh$ by real and virtual photons on a nucleon. The initial photon dissociates into a $qbar{q}$-dipole and transforms into a vector meson by scattering off the nucleon which, for simplicity, is represented as quark-diquark. The relevant dipole-dipole scattering amplitude is provided by the non-perturbative model of the stochastic QCD vacuum. The wave functions result from considerations in the frame of light-front dynamics; the physical $rh$- and $rh$-mesons are assumed to be mixed states of an active 2S-excitation and some residual rest (2D- and/or hybrid state). We obtain good agreement with the experimental data and get an understanding of the markedly different $pi^+pi^-$-mass spectra for photoproduction and $e^+e^-$-annihilation.
We calculate diffractive photo- and leptoproduction of $rho$-, $rho$- and $rho$-mesons. The incoming photon dissociates into a $qbar{q}$-dipole which scatters on the nucleon and transforms into a vector meson state. The scattering amplitude is calcul ated in non-perturbative QCD with the model of the stochastic vacuum. Assuming that the physical $rho$- and $rho$-mesons are mixed states of an active 2S-excitation and some residual hybrid state which cannot be produced diffractively in lowest order QCD, we obtain good agreement with the data, especially the markedly different spectrum in the $pi^+pi^-$-invariant mass for photoproduction and $e^+e^-$-annihilation.
We have computed the hard dilepton production rate from a weakly magnetized deconfined QCD medium within one-loop photon self-energy by considering one hard and one thermomagnetic resummed quark propagator in the loop. In the presence of the magnetic field, the resummed propagator leads to four quasiparticle modes. The production of hard dileptons consists of rates when all four quasiquarks originating from the poles of the propagator individually annihilate with a hard quark coming from a bare propagator in the loop. Besides these, there are also contributions from a mixture of pole and Landau cut part. In weak field approximation, the magnetic field appears as a perturbative correction to the thermal contribution. Since the calculation is very involved, for a first effort as well as for simplicity, we obtained the rate up to first order in the magnetic field, i.e., ${cal O}[(eB)]$, which causes a marginal improvement over that in the absence of magnetic field.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا