AnomalousZ′ effects in the WW channel at NLC

We consider the virtual signals of aZ′ of very general type in the processe ⁺ e ^?→W ⁺ W ^? at a future linear collider (NLC). We show that possible deviations from the SM predictions in this channel are related to similar deviations in the purely leptonic one in a way that is only characteristic of thisZ′ model, and not in general of possible competitor models with anomalous gauge couplings.     

New vector bosons at a 1 TeVe + e − collider

We develop a simple and realistic strategy to identify the theoretical origin of aZ′ of massM _z′ ? 400 GeV if the latter were directly produced at a futuree ⁺ e ^? collider. A measurement of the muonic width and of two ratios of hadronic to muonic widths would lead to an almost complete identification within a very general class of extraU(1) models. Alternative models, though, would be better classified by measuring three longitudinal polarization asymmetries.     

Analysis of tetrapyrrolic pigments and derivatives in sediments by high performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry

A new application is described of the on-line high-performance liquid chromatography/positive and negative ion atmospheric pressure chemical ionization mass spectrometry (APCI(+/–)-MS) to the identification of tetrapyrrolic compounds in sediment samples containing complex mixtures of natural pigments and their diagenetic products. The method relies on the production of radical anions in order to determine the molecular masses of the molecules which yield abundant fragment ions when analyzed in the positive mode. This approach allows to verify the occurrence of coeluting components by examining their negative ion spectra and to complete their identification on the basis of their fragment ions produced in the positive ion spectra. Received: 24 September 1998 / Revised: 23 December 1998 / Accepted: 29 December 1998     

Analysis of tetrapyrrolic pigments and derivatives in sediments by high performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry

A new application is described of the on-line high-performance liquid chromatography/positive and negative ion atmospheric pressure chemical ionization mass spectrometry (APCI(+/–)-MS) to the identification of tetrapyrrolic compounds in sediment samples containing complex mixtures of natural pigments and their diagenetic products. The method relies on the production of radical anions in order to determine the molecular masses of the molecules which yield abundant fragment ions when analyzed in the positive mode. This approach allows to verify the occurrence of coeluting components by examining their negative ion spectra and to complete their identification on the basis of their fragment ions produced in the positive ion spectra. Received: 24 September 1998 / Revised: 23 December 1998 / Accepted: 29 December 1998     

Rapid identification of Mg-chelated chlorins by on-line high performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry

On-line high performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS) has been applied to the identification of a number of tetrapyrrolic pigments as well as several magnesium-free analogs. Mass spectra, acquired both in positive (+) and negative (-) ionization mode, allow not only the determination of the structural features of the pigments, but also a very easy differentiation of the Mg-chelated pigments from the free bases. In the positive ionization mode, all pigments show mainly a [M + H]+ ion and a [M + H - C20H38]+ fragment ion corresponding to the loss of the phytyl chain via a hydrogen rearrangement. In the negative ionization mode, on the other hand, although all pigments give an abundant molecular anion [M]-*, only the Mg-chelated chlorin spectra show a prominent fragment [M - C20H39]- produced by a formal loss of the phytyl radical.