摘要:

We describe the use of a water Cherenkov detector to study the distributions of charge, amplitude and rise time of the signals associated to isolated electromagnetic particles, isolated muons and extended air showers in the secondary cosmic‐ray radiation. The detector consists of a polyethylene tank of 1.54 m of diameter filled with water up to a height of 1.2 with one 8″ phototube looking downwards in the center of the tank at the level of the water. The data acquisition system consists of NIM modules, one digital oscilloscope and one PC running LabView. We performed precise measurements of voltage amplitude, charge deposition, 10&percent;–90&percent; and 10&percent;–50&percent; rise times to each of the WCD signals for three different types of triggers:vertical non‐central muon, vertical central muonsandarbitrary muons. We show the existence of very strong correlations among these parameters in the signals corresponding to isolated electrons, isolated muons, muon interactions with the PMT glass envelope and extensive air showers. These correlations allow a clear separation of these components when one uses bi‐dimensional plots such as charge vs amplitude, charge vs rise time and charge vs charge/amplitude. We use our results to suggest a way in which one can measure &mgr;/EM in large ground arrays of water Cherenkov detectors such as in the case of the Pierre Auger Observatory. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594371

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Historically, the analysis of air shower data of surface arrays has been limited to events with zenith angles not bigger than 45° &ellip; 60°. In the following, we present the use of showers at larger zenith angles as a means of extending the aperture of the detector and as a tool for the detection of neutrino‐induced air showers. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594372

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

In this work a status report of a search for caves in the Sun pyramid in Teotihuacan, Me´xico is presented. From an archeological perspective the main goal is to gather evidence to determine whether the pyramid was a state or a funerary temple. The general layout of the detector that is being built is an updated version of the one originally proposed by Alvarezet al.. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594373

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The Pierre Auger Observatory, now under construction in its first stage in Argentina, will be an important tool in the solution of the puzzle of the ultra high energy cosmic rays. It will cover a total area of 6000 km2with 3200 surface Cherenkov detectors and 8 fluorescence detectors. The Pierre Auger Observatory is the result of an international effort. It has been designed to study cosmic rays with energies ⩾ 1018eV with high statistics, achieving its full efficiency at energies ⩾ 1019.5eV. In this paper, the goal and the design of the observatory are briefly described. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594374

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The first stage of the construction of the southern Pierre Auger Observatory in Argentina has finished. This stage consisted of the deployment of a smaller version of the observatory called the Engineering Array. The operation and testing of this array, which included data acquisition of events produced by ultra high energy cosmic rays for several months, have demonstrated the reliability of the Pierre Auger Observatory in order to accomplish the objectives for which it was designed: to answer the most enigmatic questions about the ultra high energy cosmic rays. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594375

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

It’s introduced a calculation, which is based on symmetries followed by high energy hadronic interactions, of resonance polarization and specific angular momentum state polarization created inpp→p(baryon). © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594376

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We study the renormalization group flow and infrared structure of higher dimensional GUTs. In higher dimensional theories the couplings approach much faster the infrared fixed points, compared to the four‐dimensional case, due to their power law running behaviour. Therefore, tighter restrictions can be imposed to the couplings at the infrared region, enhancing thus the predictivity of the theories. We take a model with SU(5) as gauge group as a concrete example and show the running behaviour of the coupling constants. We also describe the predictions of low‐energy parameters, e.g. masses of the top quark and superparticles that result from the fixed point structure of the RGEs. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594377

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We study the four‐body region of the Dalitz plot for the semileptonic decays of polarized charged baryons. We perform our calculations up to order &agr;q/&pgr;M1, whereqis the four‐momentum transfer andM1is the mass of decaying baryon. This work complements previous results obtained for the so called three‐body region of these decays where the radiative corrections are calculated up to order &agr;q/&pgr;M1. In this way we will be able to obtain the total Dalitz plot which can be used in ordinary baryon decays and in charmed baryon decays like &Lgr;c→ &Lgr;0ev. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594378

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

In semileptonic decays of spin‐1/2 baryons containing heavy quarks up to six charge assignments for the baryons and lepton are possible. We have found that the radiative corrections to four of these possibilities can be directly obtained from the final results of the two possibilities previously studied. In consequence, neither integrals over virtual or real photon momentum nor any traces need to be recalculated. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594379

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We propose the study of the positron‐electron annihilation into neutrino‐anti‐neutrino pairs (e+e−→vv¯) to get information on physics beyond the Standard Model such as a non‐zero neutrino magnetic moment (&mgr;v) or charged radius (⟨r2⟩), as well as right handed currents. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1594380

出版商:AIP    

年代:1903

数据来源: AIP