Cancellation of Infrared Divergences in Thermal QED

As a preliminary step, the radiation produced by a classical charged current coupled to a quantized $A_{\mu}$ is solved. To each order in $\alpha$, all infrared divergences cancel between the virtual $\gamma$'s and the real $\gamma$'s absorbed from the plasma or emitted into the plasma. When all orders of perturbation theory are summed, the finite answer predicts a suppression of radiation with $\omega< \alpha T$. The analysis of QED then consists of two steps. First, a general probability at $T\neq 0$ is organized so that all the virtual $e^{\pm},\gamma$ are in the amplitudes and all the real $e^{\pm},\gamma$ are in the phase space integrations. Next, the cancellations of IR divergences between virtual and real are demonstrated.Comment: 6 pages, (Talk presented at Quark Matter '93

Aktivitas Sitotoksik Fraksi Polar Ekstrak Etanol Biji Srikaya (Annona Squamosa L.) Terhadap Sel T47D

Kanker merupakan salah satu penyakit penyebab kematian terbesar. Biji Srikaya (Annona squamosa L.) diketahui mempunyai aktivitas sitotoksik terhadap sel T47D. Kandungan senyawa pada fraksi polar ekstrak etanol biji Srikaya (Annona squamosa L.) mempunyai efek menghambat proliferasi sel tumor. Tujuan penelitian ini adalah untuk mengetahui aktivitas sitotoksik fraksi polar ekstrak etanol biji Srikaya (Annona squamosa L.) terhadap sel T47D dengan parameter nilai IC50. Biji Srikaya diekstraksi dengan etanol 96% secara maserasi. Fraksi polar ekstrak etanol biji srikaya diperoleh dengan cara fraksinasi menggunakan Kromatografi Cair Vakum (KCV). Uji sitotoksik pada penelitian ini menggunakan metode MTT. Seri konsentrasi ekstrak yang digunakan adalah 5, 10, 25, 50, 100, dan 150 μg/mL. Kromatografi Lapis Tipis menggunakan fase diam silika gel GF254 dan fase gerak kloroform:metanol (8:2) untuk identifikasi golongan senyawa dalam ekstrak. Hasil penelitian menunjukkan bahwa fraksi polar ekstrak etanol biji srikaya mempunyai aktivitas sitotoksik terhadap sel T47D dengan nilai IC50 sebesar 23,34 μg/mL. Golongan senyawa kimia yang terkandung dalam ekstrak tersebut adalah alkaloid, flavonoid, dan polifenol yang dideteksi dengan reagen semprot yaitu Dragendroff, sitroborat, serta FeCl3

Kandungan Logam Berat Air Laut, Sedimen dan Daging Kerang Darah (Anadara Granosa) di Perairan Mentok dan Tanjung Jabung Timur

Pengamatan kandungan logam berat dilakukan di perairan Mentok dan Tanjung Jabung Timur pada bulan Mei, Juli dan Oktober 2002. Pengambilan contoh dilakukan pada jarak 1 mil dan jarak 2 mil dari garis pantai masing-masing pada 3 stasiun. Jenis contoh yang diambil dari tiap stasiun di lokasi perairan adalah air laut, sedimen dan kerang darah untuk dilakukan analisis kandungan logam berat dengan menggunakan metodeAtomic Absorption Spectrophotometer (AAS). Selain itu pada lingkungan perairan dilakukan pengamatan terhadap kualitas air yang meliputi: pH, salinitas, DO dan COD serta kondisi fisik perairan pada saat pengambilan contoh. Hasil penelitian menunjukkan bahwa kandungan merkuri air laut dan sedimen tertinggi diperoleh saat pengambilan contoh bulan Mei pada jarak 1 mil baik di perairan Mentok dan Tanjung Jabung Timur.Rata-rata kandungan merkuri air laut di perairan Tanjung Jabung Timur lebih tinggi (1.49 ppb) dibandingkan di perairan Mentok (1.12 ppb), untuk sedimen rata-rata kandungan merkuri lebih tinggi di perairan Tanjung Jabung Timur (4.95 ppb) dibandingkan di perairan Mentok (3.89 ppb). Rata-rata kandungan logam berat daging kerang darah (Anadara granosa) di perairan Tanjung Jabung Timur (Hg: 0.4 ppb, As: 12.6 ppb, Cd: 13ppb, Cu: 10.4 ppb, Pb: 0.1 ppb) lebih tinggi dibandingkan di perairan Mentok (Hg: 0.3 ppb, As: 11.6 ppb, Cd: 13 ppb, Cu: 6 ppb, Pb: 0.1 ppb). Hasil penelitian menunjukkan bahwa perairan Mentok dan Tanjung Jabung Timur belum terindikasi tercemar logam berat karena masih berada dibawah ambang batas aman

Double logarithmical corrections to beam asymmetry in polarized electron-proton scattering

The up-down asymmetry in transversally polarized electron proton scattering is induced by the interference between one and two photon exchange amplitudes. Inelastic intermediate hadronic states (different from one-proton state) of the two photon exchange amplitude give rise to contributions containing the square of "large logarithm" (logarithm of the ratio of the transferred momentum to the electron mass). We investigate the presence of such contributions in higher orders of perturbation theory. The relation with the case of zero transfer momentum is explicitly given. The mechanism of cancellation of infrared singularities is discussed.Comment: 9 pages, 8 figure

Coulomb corrections for quasielastic (e,e') scattering: eikonal approximation

We address the problem of including Coulomb distortion effects in inclusive quasielastic (e,e') reactions using the eikonal approximation. Our results indicate that Coulomb corrections may become large for heavy nuclei for certain kinematical regions. The issues of our model are presented in detail and the results are compared to calculations of the Ohio group, where Dirac wave functions were used both for electrons and nucleons. Our results are in good agreement with those obtained by exact calculations.Comment: 29 pages, 10 figures, LATEX (elsart.cls). Final version to be publishe

Near threshold radiative 3π\pi production in e+e−e^+e^- annihilation

We consider the $\pi^+\pi^-\pi_0\gamma$ final state in electron-positron annihilation at cms energies not far from the threshold. Both initial and final state radiations of the hard photon is considered but without interference between them. The amplitude for the final state radiation is obtained by using the effective Wess-Zumino-Witten Lagrangian for pion-photon interactions valid for low energies. In real experiments energies are never such small that $\rho$ and $\omega$ mesons would have negligible effect. So a phenomenological Breit-Wigner factor is introduced in the final state radiation amplitude to account for the vector mesons influence. Using radiative 3$\pi$ production amplitudes, a Monte Carlo event generator was developed which could be useful in experimental studies.Comment: 15 pages, Latex, 6 figures. Misprints corrected. Version to be published in JHE

Monte Carlo simulation for radiative kaon decays

For high precision measurements of K decays, the presence of radiated photons cannot be neglected. The Monte Carlo simulations must include the radiative corrections in order to compute the correct event counting and efficiency calculations. In this paper we briefly describe a method for simulating such decays.Comment: 11 pages, 1 figur

Bremsstrahlung Radiation as Coherent State in Thermal QED

Based on fully finite temperature field theory we investigate the radiation probability in the bremsstrahlung process in thermal QED. It turns out that the infrared divergences resulting from the emission and absorption of the real photons are canceled by the virtual photon exchange processes at finite temperature. The full quantum calculation results for soft photons radiation coincide completely with that obtained in the semi-classical approximation. In the framework of Thermofield Dynamics it is shown that the bremsstrahlung radiation in thermal QED is a coherent state, the quasiclassical behavior of the coherent state leads to above coincidence.Comment: 8 pages, 2 figure

QCD soft gluon exponentiation: YFS MC Approach

We develop and prove the theory of the QCD extension of the YFS Monte Carlo approach to higher order QED radiative corrections. As a corollary, a new approach to quantum gravity by one of us (B.F.L.W.) is illustrated. Semi-analytical results and preliminary explicit Monte Carlo data are presented for the processes p-bar p -> t-bar t + X at FNAL energies. We comment briefly on the implications of our results on the CDF/D0 observations and on RHIC/LHC physics.Comment: 4 pages, 2 figures, presented at ICHEP02 by BFL