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The instanton liquid and the axion
No full textThe ultimate goal of this thesis is to improve our understanding of the cosmology of axions. Axions couple to QCD
instantons and these non-perturbative effects are modeled within the framework of the interacting instanton liquid model (IILM). The thesis describes the significant advances made within the IILM in order to study the quark-gluon plasma in realistic parameter regimes. In particular, a determination of the temperature-dependent axion mass in the IILM lays the foundation for a critical reevaluation and update of present cosmological axion constraints.
We develop grand canonical Monte Carlo routines to study topological fluctuations in the quark-gluon plasma. The model is calibrated against the topological susceptibility at zero temperature, in the chiral regime of physical quark masses. A numerical framework to derive interactions among the pseudo-particles is developed that is in principle exact, and is used to cure a pathology in the presently available finite temperature interactions.
The IILM reduces field theory to a molecular dynamics description, and we show that, quite generically, the dynamics for non-trivial backgrounds in the presence of light quarks is reminiscent of a strongly associating fluid. To deal with the well-known difficulty in simulating ionic fluids, we develop advanced algorithms based on Biased Monte Carlo techniques.
We study the IILM at finite temperature in the quenched and unquenched sector, with due diligence to a consistent thermodynamic limit. Of particular interest is chiral symmetry breaking and the temperature dependence of the topological susceptibility, and we study in detail the effects of instanton--anti-instanton pairs. Our determination of the topological susceptibility provides, for the first time, a well-motivated axion mass for all temperatures.
The misalignment mechanism for axion production is studied in detail, solving the evolution equations exactly in a radiation dominated FRW universe with the full temperature dependence of the effective degrees of freedom taken into account. Improved constraints in the classic and anthropic axion window are derived. We generalise the latter to large angle fine-tuning by including in the isocurvature contribution to the cosmic microwave background radiation the full anharmonic axion potential effects. Finally, we reexamine bounds from axion string radiation in the thermal scenario to complete a comprehensive update of all cosmological axion constraints
A Precise measurement of the partial decay width ratio R(b)**0 = Gamma(b anti-b) / Gamma(had)
No full textThe partial decay width of the Z to b (b) over bar quark pairs has been measured by the DELPHI detector at LEP using data taken in the years 1992 to 1995. Decays of b-hadrons were tagged by several methods using tracks with large impact parameters and/or reconstructed secondary vertices; complemented by event shape variables. Combining these methods in a multivariate analysis the value Gamma(Z --> b (b) over bar)/Gamma(Z --> had) = 0.21634 +/- 0.00067(stat) +/- 0.00060(syst) was obtained, where the c (c) over bar production fraction was fixed to its Standard Model value. RI De Angelis, Alessandro/B-5372-2009; Ragazzi, Stefano/D-2463-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Muresan, Raluca-Anca/C-3725-2011; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Monge, Maria Roberta/G-9127-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-201
Simulation of the fluorescence detector of the Pierre Auger Observatory
No full textWe present a description of a simulation program for the fluorescence detector (FD) of the Pierre Auger Observatory. The simulation chain covers in detail all the physical processes involved in the fluorescence technique, from the shower longitudinal profile in the atmosphere to ADC-traces in the data acquisition system of the telescopes. Steps in the simulation include the generation of fluorescence and Cherenkov light in the atmosphere, propagation of this light to the telescope aperture, ray-tracing of photons in the Schmidt optics of the telescopes, and finally, simulation of the response of the electronics and the multi-level trigger. As an example of the simulation's use we show the results of a calculation of the trigger efficiency of the FD as a function of cosmic ray energy. (c) 2005 Elsevier B.V. All rights reserved
Search for neutralino pair production at root s = 189 GeV
No full textA search for pair-production of neutralinos at a LEP centre-of-mass energy of 189 GeV gave no evidence for a signal. This limits the neutralino production cross-section and excludes regions in the parameter space of the Minimal Supersymmetric Standard Model (MSSM). RI Ragazzi, Stefano/D-2463-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Andreazza, Attilio/E-5642-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Monge, Maria Roberta/G-9127-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-201
Topological events on wave dislocation lines: birth and death of small loops, and reconnection
No full textIn three-dimensional space, a wave dislocation, that is, a quantized (optical) vortex or phase singularity, is a line zero of a complex scalar wavefunction. As a 'time' parameter varies, the topology of the vortex can change by encounter with a line of vanishing vorticity (curl of the current associated with the wavefunction). An isolated critical point of the field intensity, sliding along the zero-vorticity line like a bead on a wire, meets the vortex as it encounters the line, and so participates in the singular event. Local expansio n and gauge and coordinates transformations show that the vortex topology can change generically by the appearance or disappearance of a loop, or by the reconnection of branches of a pair of hyperbolas
Measurement of A(FB)(b(b)over-bar) in hadronic Z decays using a jet charge technique
No full textThe bb forward-backward asymmetry has been determined from the average charge how measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched b (b) over bar sample selected using an impact parameter tag and results in the following values for the bl; forward-backward asymmetry: A(FB)(b (b) over bar) (89.55 GeV) = 0.068 +/- 0.016 (stat.) +/- 0.0013(syst.) A(FB)(b (b) over bar)(91.26 GeV) = 0.0982 +/- 0.0047(stat.) +/- 0.0016(syst.) A(FB)(b (b) over bar)(92.94 GeV) = 0.123 +/- 0.016 (stat.) +/- 0.0027(syst.) The b (b) over bar charge separation required for this analysis is directly measured in the b tagged sample, while the other charge separations are obtained from a fragmentation model precisely calibrated to data. The effective weak mixing angle is deduced from the measurement to be: sin(2)theta(eff)1 = 0.23186 +/- 0.00063. RI De Angelis, Alessandro/B-5372-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Muresan, Raluca-Anca/C-3725-2011; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Monge, Maria Roberta/G-9127-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-201
SMARANDACHE MULTI-SPACE THEORY, Second Edition
No full textWe are used to the idea that our space has three dimensions: length, breadth and height with time providing the fourth dimension of spacetime by Einstein. In the string or superstring theories, we encounter 10 dimensions. However, we do not even know what the right degree of freedom is, as Witten said. Today, we have known two heartening notions for sciences. One is the Smarandache multi-space came into being by purely logic. Another is the mathematical combinatorics motivated by a combinatorial speculation, i.e., a mathematical science can be reconstructed from or made by combinatorialization. Both of them contribute sciences for consistency of research with that human progress in 21st century
Harmony and discord within the English ‘counter-culture’, 1965-1975, with particular reference to the ‘rock operas’ Hair, Godspell, Tommy and Jesus Christ Superstar
No full textPhDThis thesis considers the discrete, historically-specific theatrical and musical sub-genre of ‘Rock Opera’ as a lens through which to examine the cultural, political and social changes that are widely assumed to have characterised ‘The Sixties’ in Britain. The musical and dramatic texts, creation and production of Hair (1967), Tommy (1969), Godspell (1971), Jesus Christ Superstar (1970) and other neglected ‘Rock Operas’ of the period are analysed. Their great popularity with ‘mainstream’ audiences is considered and contrasted with the overwhelmingly negative and often internally contradictory reaction towards them from the English ‘counter-culture’. This examination offers new insights into both the ‘counter-culture’ and the ‘mainstream’ against which it claimed to define and differentiate itself.
The four ‘Rock Operas’, two of which are based upon Christian scriptures, are considered as narratives of spiritual quest. The relationship between the often controversial quests for re-defined forms of faith and the apparently precipitous ‘secularization’ and ‘de-Christianization’ of British society during the 1960s and 1970s is considered.
The thesis therefore analyses the ‘Rock Operas’ as significant, enlightening prisms through which to view many of the profound societal debates – over ‘faith’ and ‘belief’ in the widest senses, sexuality, the Vietnam war, generational conflict, drugs and ‘spiritual enlightenment’, and race – which were, to some considerable extent, elevated onto the national, political agenda by the activities of the broadly-defined ‘counter-culture’. It considers subsequent representations of the ‘counter-culture’ as the root of a contested but enduring popular legacy of ‘The Sixties' as a period of profound cultural change
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