Unresolved Radiation Research Articles

The scales of the infrared

In theories with long-range forces like QED or perturbative gravity, loop corrections lead to vanishing amplitudes. There are two well-known procedures to address these infrared divergences: dressing of asymptotic states and inclusion of soft emission. Although both yield the same IR-finite rates, we point out that they are not equivalent since they encode different infrared scales. In particular, dressing states are independent of the resolution scale of radiation. Instead, they define radiative vacua in the von Neumann space. After a review of these concepts, the goal of this paper is to present a combined formalism that can simultaneously describe both dressing and radiation. This unified approach allows us to tackle the problem of quantum decoherence due to tracing over unresolved radiation. We obtain an IR-finite density matrix with non-vanishing off-diagonal elements and estimate how its purity depends on scattering kinematics and the resolution scale. Along the way, we comment on collinear divergences as well as the connection of large gauge transformations and dressing.

Antenna subtraction at NNLO with hadronic initial states: double real initial-initial configurations

Abstract The antenna subtraction method handles real radiation contributions in higher order corrections to jet observables. The method is based on antenna functions, which encapsulate all unresolved radiation between a pair of hard radiator partons. To apply this method to compute hadron collider observables, initial-initial antenna functions with both radiators in the initial state are required in unintegrated and integrated forms. In view of extending the antenna subtraction method to next-to-next-to-leading order (NNLO) calculations at hadron colliders, we derive the full set of initial-initial double real radiation antenna functions in integrated form.

Antenna subtraction at NNLO with hadronic initial states: real-virtual initial-initial configurations

The antenna subtraction method handles real radiation contributions in higher order corrections to jet observables. The method is based on antenna functions, which encapsulate all unresolved radiation between a pair of hard radiator partons. To apply this method to compute hadron collider observables, initial-initial antenna functions with both radiators in the initial state are required. In view of extending the antenna subtraction method to next-to-next-to-leading order (NNLO) calculations at hadron colliders, we derive the one-loop initial-initial antenna functions in unintegrated and integrated form.

Antenna subtraction at NNLO with hadronic initial states: double real radiation for initial-initial configurations with two quark flavours

The antenna subtraction formalism allows to calculate QCD corrections to jet observables. Within this formalism, the subtraction terms are constructed using antenna functions describing all unresolved radiation between a pair of hard radiatior partons. In this paper, we focus on the subtraction terms for double real radiation contributions to jet observables in hadron-hadron collisions evaluated at NNLO. An essential ingredient to these subtraction terms are the four-parton antenna functions with both radiators in the initial state. We outline the construction of the double real subtraction terms, classify all relevant antenna functions and describe their integration over the relevant antenna phase space. For the initial-initial antenna functions with two quark flavours, we derive the phase space master integrals and obtain the integrated antennae.

A randomized phase II study of gemcitabine (G) vs gemcitabine/carboplatin (GC) as consolidation therapy to concurrent chemoradiotherapy (CRT) for stage III non-small cell lung cancer (NSCLC): A Lung Cancer Research Group (LCRG) study

7559 Background: Consolidation chemotherapy following concurrent CRT may improve systemic control and possibly prolong survival of pt with stage III NSCLC. Phase II study using docetaxel showed promising result but subsequent phase III study was negative. We explored the role of single agent gemcitabine (G) and combination with carboplatin (C) as consolidation chemotherapy. Methods: Study was conducted by Asian mutli-center group. Eligible criteria: stage IIIA/B, histologic/cytologic confirmed NSCLC, completed concurrent CRT according to preset cisplatin and RT doses, attained CR/PR/SD from CRT, randomized within 6 weeks from last day of CRT, ECOG 0–1, adequate organ function, no brain met. Exclusion: unresolved radiation pneumonitis/esophagitis. Randomized to G at 1250mg/m2 day 1,8 q21d x3 or G at same dose plus C at 5 x AUC at day 1 x3. Primary and 2nd end points are 2-yr survival rate, median survival and toxicity, respectively. Sample size was estimated to detect a 15% difference in 2 yrs survival rate. Results: Between 3/04 and 6/06 we screened 111 pts and enrolled 61. 10 pts were excluded because of unresolved pneumonitis/esophagitis. Pt characteristics are similar between 2 arms.(Table) Median age: 56. Dose of RT/cisplatin during CRT were similar. 3 pts in G arm skipped day 8 G while 10 in GC arm (p=0.16). 3 pt and 2 pt attained higher response status during G and GC respectively, while 3 and 4 pt progressed. Survival outcomes are similar. More hematologic toxicity in GC arm (G3/4 Anemia 3 v 44%; Neutro 25 v 51%; Plat 15.6 v 31%) 5 out of 61 pt had grade 3/4 post gemcitabine radiation pneumonitis and all 5 are from G arm. Conclusion: It is feasible to give G-based consolidation chemotherapy in selected patients after concurrent CRT. Combination therapy with platinum did not improve survival but it added to myelotoxicity. “Re-call” radiation pneumonitis by gemcitabine is relatively uncommon. Patient Characteristics and Primary Efficacy G (n=32) GC (n-29) p M/F 29/3 26/3 IIIA/IIIB 5/27 7/22 0.4 Adenocarcinoma/Non-adenocinoma 15/17 13/16 0.87 Median # of cycles 2 2 0.84 2 yr survival rate 46.3% 42.2% 0.89 1 yr progression free rate 34.4% 38.7% 0.53 Median survival 1.78 yr 1.75 yr 0.98 Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Abraxis, AstraZeneca, Eli Lilly, GlaxoSmithKline, Novartis, Pfizer, Roche AstraZeneca, Eli Lilly, Merck, Novartis, Pfizer, Roche Bayer, Novartis

Nonequilibrium Processes During Fe(CO)5 Pyrolysis in a Shock Wave

In this work the processes of nonequilibrium radiation and ionization in the weak shock waves (2 < M < 4) in argon or helium, containing a small admixture (0.1–2%) of Fe(CO)5 are experimentally studied. The spectra- and time-resolved measurements, performed using a ICCD camera (StreakStar II, LaVision GmbH) have shown, that the unresolved radiation spectra are situated in the range 400–700 nm. The maximum of the spectra lies approximately at 615 nm. The radiation appeared immediately at the propagating shock front and lasted about 8–12 μs. The following time-resolved measurements, performed using photomultipliers (at 615 ± 10 nm) and calibrated electric probes have shown intensive peaks of emission and electric current with duration of few μs, that correlates with the characteristic time of active growth of iron clusters. The analysis of the results obtained allowed to conclude that the real mechanism of generation of the observed peaks of radiation and ionization is the instant dissociation of Fe(CO)5 causing an active condensation process of a supersaturated vapor of iron atoms, which results in the formation of excited and ionized iron clusters.

Monophyly of the Asteridae and Identification of Their Major Lineages Inferred From DNA Sequences of rbcL

A parsimony analysis of 57 angiosperm rbcL sequences was conducted to test the monophyly of the Asteridae and to identify major lineages within the Asteridae. Three major clades, the Caryophyllidae, the Rosidae plus Dilleniidae, and the Asteridae sensu lato, emerge from an unresolved radiation in the «higher» dicots. The Asteridae sens. lat. include the Ericales, Cornales, and Apiales in addition to the Asteridae sens. str. Two major lineages within the Asteridae sens. lat. are identified: the Dipsacales, Apiales, Asterales, and Campanulales in one, and the Gentianales, Scrophulariales, Lamiales, Boraginales, and Solanales in the other (...)

Atomic, molecular, and continuum radiation from ion-bombarded B and B 2O 3

Inert-gas ion impact on elemental boron and B 2O 3 in the presence of hydrogen or oxygen containing gases results in a rich variety of atomic, molecular, and “continuum” optical emission. In the presence of gaseous O 2, some 20 different features due to OII are observed with elemental B. These are the first oxygen photon signals in the visible reported in a sputtering experiment. Independent of the gas present, B 2O 3 yields unresolved radiation (“continuum”), the latter coinciding with the general region of the A 2Π → X 2Σ + system of BO. Bombardment of elemental B in the presence of gaseous H 2 or CH 4 leads to emission from the A 1Π → X 1Σ + system of BH. The BH molecule can be characterized in terms of an effective rotational “temperature” (2700–3800 K), a kinetic-energy threshold (12–20 eV), and a saturation-type dependence of the signal on the beam current. Radiation from the BH molecule was observed to be surprisingly intense. We note that the emitting A 1Π state correlates adiabatically with groundstate B and H atoms. It is hypothesized that this may play a major role in the mechanism of ion-bombardment-induced creation of molecular excited species.

Photo-Electric Ionization of Caesium Vapor

Measurement of photo-electric ionization in gases.---The current from a filament, normally limited by space change, is increased by the presence of positive ions. As shown by Kingdon this effect may be greatly magnified if a small cathode is practically enclosed by the anode so that the ions are imprisoned. This method was used for the detection of photo-electric ionization. Besides possessing extreme sensitivity it is unaffected by photo-electric emission from the electrodes.Photo-electric effect in caesium vapor.---The change in thermionic current with the unresolved radiation from a mercury arc was measured as functions of the applied voltage, filament temperature, and vapor pressure. Then the photo-electric effect as a function of wave-length was studied using a monochromatic illuminator to disperse light from the arc or a Mazda lamp. The ionization per unit flux was found to increase with increasing wave-length to a sharp maximum at the limit $1s=3184$A of the principal series, as is required by the Bohr theory. For longer wave-lengths the ionization decreased to about 10 percent at 3400A. Photo-excitation. The simple theory does not admit of ionization by wave-lengths greater than 3184A but the data are in qualitative agreement with the hypothesis that such radiation produces excited atoms which upon collision with other atoms acquire sufficient additional energy to become ionized. Hence, unlike an x-ray limit, the photo-ionization effect for a valence electron is not sharply discontinuous at the true threshold for direct ionization.Photo-ionization photometer and intensitometer. A tube of the type described, with suitable gases for the range of wave-length involved, may be used as a photometer or may be calibrated to measure intensity of radiation directly.