44393741
PEP-N detector layout
We describe a possible experimental apparatus for a proposed new experiment to be carried out at an asymmetrical collider, consisting of the PEP-II Low Energy Ring (LER) and a new electron storage ring (Very Low Energy Ring, VLER) of energy 100 MeV < Ee < 800 MeV . The accessible center of mass (CM) energy will then be 1.2 GeV < √ s < 3.15 GeV . While there are many important physics measurements that are feasible at this collider, a lot of emphasis will be on R, the ratio of the hadron and muon pair cross sections, and on the determination of nucleon form factors. This paper is organized as follows: the main physics motivations will be outlined in section 2. The measurement method of R and the experimental requirements will be the subject of section 3, while the detector requirements will be discussed in section 4. Section 5 will be devoted to rates and running time. The detector layout will then be presented in section 6. The individual detector components will be briefly described in section 7 (a full description can be found in the dedicated papers in these proceedings). Finally in section 8 we will present our conclusions.
108986863
Performance measurements of histe-V VLPC photon detectors for E835 at FNAL
A set of 144 VLPC chips has been used by experiment E835 at FNAL for the readout of its scintillating fiber detector. During the data taking, the fibers have been exposed to rates up to 2.5×104 mips/sec, corresponding to 3.5×106 photons/sec on each VLPC pixel surface. This paper reports about a study on rate dependence of gain and quantum efficiency throughout the run, as well as VLPC failure statistics during operation. No significant aging effects are observed. A review about the overall system performance is given.
119627299
HIGH-RESOLUTION SILICON DETECTORS FOR COLLIDING BEAM PHYSICS
Abstract Resolution and linearity of the position measurement of Pisa multi-electrode silicon detectors are presented. The detectors are operated in slightly underdepleted mode and take advantage of their intrinsic resistivity for resistive charge partition between adjacent strips. 22 μm resolution is achieved with readout lines spaced 300 μm. Possible applications in colliding beam experiments for the detection of secondary vertices are discussed.
123064237
The charged trigger of the experiment E835 at Fermilab
Abstract Fermilab experiment E835 studies the charmonium states primarily through their electromagnetic decays. A kinematical charged trigger has been designed to select the electromagnetic final states e + e − and e + e − X and the hadronic decay c c → φφ →4 K ± . A detailed description of the charged trigger is presented here. The design, its implementation and the performances are given.
119936495
Hadronic Physics with Antiprotons at FAIR
The physics program of the future FAIR facility covers a wide range of topics that address central issues of strong interactions and QCD. The antiproton beam of unprecedented quality in the momentum range from 1 GeV/c to 15 GeV/c will allow to make high precision, high statistics measurements, from charmonium spectroscopy to the search for exotic hadrons and the study of nucleon structure, from the study of in-medium modifications of hadron masses to the physics of hypernuclei. These topics form the scientific program of the PANDA experiment. In addition to that the possibility to polarize antiprotons will provide the possibility to perform new, unique measurements of single- and double-spin observables, which are part of the experimental program of PAX.
125331327
The Fermilab anti-p accumulator ring for the charmonium experiment
119467863
Properties of Isolated Disk Galaxies
We present a new sample of northern isolated galaxies, which are defined by the physical criterion that they were not affected by other galaxies in their evolution during the last few Gyr. To find them we used the logarithmic ratio, f , between inner and tidal forces acting upon the candidate galaxy by a possible perturber. The analysis of the distribution of the f -values for the galaxies in the Coma cluster lead us to adopt the criterion f ≤− 4.5 for isolated galaxies. The candidates were chosen from the CfA catalog of galaxies within the volume defined bycz ≤ 5000 km s −1 , galactic latitude higher than 40 ◦ and declination ≥−2.5 ◦ . The selection of the sample, based on redshift values (when available), magnitudes and sizes of the candidate galaxies and possible perturbers present in the same field is discussed. The final list of selected isolated galaxies includes 203 objects from the initial 1706. The list contains only truly isolated galaxies in the sense defined, but it is by no means complete, since all the galaxies with possible companions under the f -criterion but with unknown redshift were discarded. We also selected a sample of perturbed galaxies comprised of all the disk galaxies from the initial list with companions (with known redshift) satisfying f ≥− 2a nd∆(cz) ≤ 500 km s −1 ; a total of 130 objects. The statistical comparison of both samples shows significant differences in morphology, sizes, masses, luminosities and color indices. Confirming previous results, we found that late spiral, Sc-type galaxies are, in particular, more frequent among isolated galaxies, whereas Lenticular galaxies are more abundant among perturbed galaxies. Isolated systems appear to be smaller, less luminous and bluer than interacting objects. We also found that bars are twice as frequent among perturbed galaxies compared to isolated galaxies, in particular for early Spirals and Lenticulars. The perturbed galaxies have higher LFIR/LB and Mmol/LB ratios, but the atomic gas content is similar for the two samples. The analysis of the luminosity-size and mass-luminosity relations shows similar trends for both families, the main difference being the almost total absence of big, bright and massive galaxies among the family of isolated systems, together with the almost total absence of small, faint and low mass galaxies among the perturbed systems. All these aspects indicate that the evolution induced by interactions with neighbors would proceed from late, small, faint and low mass Spirals to earlier, bigger, more luminous and more massive spiral and lenticular galaxies, producing at the same time a larger fraction of barred galaxies but preserving the same relations between global parameters. The properties we found for our sample of isolated galaxies appear similar to those of high redshift galaxies, suggesting that the present-day isolated galaxies could be quietly evolved, unused building blocks surviving in low density environments.
6876471
WINGS: A WIde-field Nearby Galaxy-cluster Survey - II. Deep optical photometry of 77 nearby clusters
Context: This is the second paper of a series devoted to the WIde Field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long term project which is gathering wide-field, multi-band imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04 < z < 0.07) located far from the galactic plane (|b|≥ 20°). The main goal of this project is to establish a local reference for evolutionary studies of galaxies and galaxy clusters. Aims: This paper presents the optical (B,V) photometric catalogs of the WINGS sample and describes the procedures followed to construct them. We have paid special care to correctly treat the large extended galaxies (which includes the brightest cluster galaxies) and the reduction of the influence of the bright halos of very bright stars. Methods: We have constructed photometric catalogs based on wide-field images in B and V bands using SExtractor. Photometry has been performed on images in which large galaxies and halos of bright stars were removed after modeling them with elliptical isophotes. Results: We publish deep optical photometric catalogs (90% complete at V ~ 21.7, which translates to ˜ M^*_V+6 at mean redshift), giving positions, geometrical parameters, and several total and aperture magnitudes for all the objects detected. For each field we have produced three catalogs containing galaxies, stars and objects of "unknown" classification (~6%). From simulations we found that the uncertainty of our photometry is quite dependent of the light profile of the objects with stars having the most robust photometry and de Vaucouleurs profiles showing higher uncertainties and also an additional bias of ~-0.2^m. The star/galaxy classification of the bright objects (V < 20) was checked visually making negligible the fraction of misclassified objects. For fainter objects, we found that simulations do not provide reliable estimates of the possible misclassification and therefore we have compared our data with that from deep counts of galaxies and star counts from models of our Galaxy. Both sets turned out to be consistent with our data within ~5% (in the ratio galaxies/total) up to V ~ 24. Finally, we remark that the application of our special procedure to remove large halos improves the photometry of the large galaxies in our sample with respect to the use of blind automatic procedures and increases (~16%) the detection rate of objects projected onto them. Based on observations taken at the Issac Newton Telescope (2.5 m-INT) sited at Roque de los Muchachos (La Palma, Spain), and the MPG/ESO-2.2 m Telescope sited at La Silla (Chile). Appendices are only available in electronic form at http://www.aanda.org Catalog is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/497/667
11688905
Isolated galaxies: residual of primordial building blocks?
Context. The mass assembly is believed to be the dominant process of early galaxy formation. This mechanism of galaxy building can proceed either by repeated major mergers with other systems, or by means of accretion of matter from the surrounding regions. Aims. In this paper we compare the properties of local disk galaxies that appear isolated, i.e., not tidally affected by other galaxies during the last few Gyr within the volume given by cz ≤ 5000 km s −1 , with those galaxies at z values from 0.25 to 5. Methods. Effective radii for 203 isolated galaxies and 1645 galaxies from the RC3 have been collected and the two samples have been analyzed statistically. A similar comparison has been made with half light radii studied at high z from the literature. Results. We found that isolated galaxies are, in general, smaller than other present epoch galaxies from the RC3. We notice the lack of systems larger than 7 kpc among them. Their size distribution appears to be similar to that of galaxies at 1.4 ≤ z ≤ 2. The models of the merging history also indicate that the isolated galaxies did stop their merging process at about that redshift, evolving passively since then. The galaxy density seems to have remained unchanged since that epoch Conclusions. Isolated galaxies appear to be the end products of the merging process, as proposed by the hierarchical accretion scenario at around z = 1.4. For this class of galaxies, this was the last significant merging event in their lives, and they have evolved passively since then. This is confirmed by the analytical estimate of the merging fraction with z and by the comparison with sizes of distant galaxies.
119378000
The fundamental plane of radio galaxies
We collected photometrical and dynamical data for 73 low red-shift ( z< 0:2) Radio Galaxies (LzRG) in order to study their Fundamental Plane (FP). For 22 sources we also present new velocity dispersion data that complement the photometric data given in our previous study of LzRG (Govoni et al. 2000a). It is found that the FP of LzRG is similar to the one dened by non-active elliptical galaxies, with LzRG representing the brightest end of the population of early type galaxies. Since the FP mainly reflects the virial equilibrium condition, our result implies that the global properties of early{type galaxies (dening the FP) are not influenced by the presence of gas accretion in the central black hole. This is fully in agreement with the recent results in black hole demography, showing that virtually all luminous spheroidal galaxies host a massive black hole and therefore may potentially become active. We conrm and extend to giant ellipticals the systematic increase of the mass-to-light ratio with galaxy luminosity.
116893524
The scaling relation of early-type galaxies in clusters - II. Spectroscopic data for galaxies in eight nearby clusters
Aims. We present in this work low and intermediate resolution spectroscopic data collected for 152 early type galaxies in 8 nearby clusters with z � 0.10. Methods. We use low resolution data to produce the redshift and the K-correction for every individual galaxy, as well as to give their overall spectral energy distribution, and some spectral indicators, including the 4000u break, the Mg2 strength, and the NaD equivalent width.We have also obtained higher resolution data for early type galaxies in three of the clusters, to determine their central velocity dispersion. Results. The effect of the resolution on the measured parameters is discussed. Conclusions. New accurate systemic redshift and velocity dispersion is presented for four of the surveyed clusters, A98, A3125, A3330, and DC2103-39. We have found that the K-correction values for E/S0 bright galaxies in a given nearby clusters are very similar. We also find that the distribution of the line indicators significantly differ from cluster to cluster.