High Energy Physics

Recently, Banãdos, Silk and West (BSW) demonstrated that the extremal Kerr black hole can act as a particle accelerator with arbitrarily high center-of-mass energy (E CM) when the collision takes place near the horizon. The rotating Hayward's regular black hole, apart from Mass (M) and angular momentum (a), has a new parameter g (g > 0 is a constant) that provides a deviation from the Kerr black hole. We demonstrate that for each g, with M = 1, there exist critical a E and r E H , which corresponds to a regular extremal black hole with degenerate horizons, and a E decreases whereas r E H increases with increase in g. While a < a E describe a regular non-extremal black hole with outer and inner horizons. We apply the BSW process to the rotating Hayward's regular black hole, for different g, and demonstrate numerically that the E CM diverges in the vicinity of the horizon for the extremal cases thereby suggesting that a rotating regular black hole can also act as a particle accelerator and thus in turn provide a suitable framework for Plank-scale physics. For a non-extremal case, there always exist a finite upper bound for the E CM , which increases with the deviation parameter g.

We analyze the pair production of charged particles in two-dimensional Anti-de Sitter space (AdS_2) with a constant, uniform electric field. We compute the production rate both at a semi-classical level, viewing Schwinger pair production as a tunneling event, and at the full quantum level, by extracting the imaginary part of the one-loop amplitude. In contrast to the usual Schwinger pair production in flat space, pair production in AdS_2 requires a sufficiently large electric field E^2&gt; M^2+1/4 in order to overcome the confining effect of the AdS geometry -- put in another way, the presence of an electric field E raises the Breitenlohner-Freedman bound to M^2 &gt; -1/4 + E^2. For E greater than this threshold, the vacuum is unstable to production of charged pairs in the bulk. We expect our results to be helpful in constructing supersymmetric AdS_2 X S^2 perturbative string vacua, which enter in the near-horizon limit of extremal charged black holes. Although the generalized Breit...

We investigate a new structure for machine learning classifiers applied to problems in high-energy physics by expanding the inputs to include not only measured features but also physics parameters. The physics parameters represent a smoothly varying learning task, and the resulting parameterized classifier can smoothly interpolate between them and replace sets of classifiers trained at individual values. This simplifies the training process and gives improved performance at intermediate values, even for complex problems requiring deep learning. Applications include tools parameterized in terms of theoretical model parameters, such as the mass of a particle, which allow for a single network to provide improved discrimination across a range of masses. This concept is simple to implement and allows for optimized interpolatable results.

One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 MeV0amu with charge state 1 currently do not exist. Hence, the stripping cross sections used to model the performance of heavy ion fusion driver beams have, up to now, been based on theoretical calculations. We have investigated experimentally the stripping of 3.4 MeV0amu Kr ϩ7 and Xe ϩ11 in N 2 ; 10.2 MeV0amu Ar ϩ6 in He, N 2 , Ar, and Xe; 19 MeV0amu Ar ϩ8 in He, N 2 , Ar, and Xe; 30 MeV He ϩ1 in He, N 2 , Ar, and Xe; and 38 MeV0amu N ϩ6 in He, N 2 , Ar, and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters.

We construct in the context of the AdS/CFT correspondence degenerate composite operators in the conformal field theory that are holographically dual to degenerate stars in anti de Sitter space. We calculate the effect of the gravitational back-reaction using the Tolman-Oppenheimer-Volkoff equations, and determine the "Chandrasekhar limit" beyond which the star undergoes gravitational collapse towards a black hole.

It is argued that string theory predicts unified field theory rather than general relativity coupled to matter fields. In unified field theory all the objects are geometrical, for strings the Kalb-Ramond matter field is identical to the asymmetric part of the metric except that the fields contribute to different sides of the field equations. The dilaton is related to the object of non-metricity.

We discuss how to extract information about the cosmological constant from the Wheeler-DeWitt equation, considered as an eigenvalue of a Sturm-Liouville problem. The equation is approximated to one loop with the help of a variational approach with Gaussian trial wave functionals. A canonical decomposition of modes is used to separate transverse-traceless tensors (graviton) from ghosts and scalar. We show that no ghosts appear in the final evaluation of the cosmological constant. A zeta function regularization is used to handle with divergences. A renormalization procedure is introduced to remove the infinities together with a renormalization group equation. A brief discussion on the extension to a f(R) theory is considered.

We study N = 2 supersymmetric SU(2) gauge theories coupled to non-Lagrangian superconformal field theories induced by compactifying the six dimensional A 1 (2,0) theory on Riemann surfaces with irregular punctures. These are naturally associated to Hitchin systems with wild ramification whose spectral curves provide the relevant Seiberg-Witten geometries. We propose that the prepotential of these gauge theories on the Ω-background can be obtained from the corresponding irregular conformal blocks on the Riemann surfaces via a generalization of the coherent state construction to the case of higher order singularities.

We present the calculation of all non-planar master integrals that are needed to describe production of two off-shell vector bosons in collisions of two massless partons through NNLO in perturbative QCD. The integrals are computed analytically using differential equations in external kinematic variables and expressed in terms of Goncharov polylogarithms. These results provide the last missing ingredient needed for the computation of two-loop amplitudes that describe the production of two gauge bosons with different invariant masses in hadron collisions.

The fundamental holographic principle is first proposed, then demonstrated in its validity and viability through a thought experiment and then finally derived. The Heisenberg uncertainty relations are shown to follow from this fundamental relation. The quantum blackhole entropy is then demonstrated using this holographic uncertainty relation along with the application of the Landauer’s principle for the thermodynamic erasure of a bit yielding a formula with a logarithmic correction. The blackhole entropy is found to be half the value normally delivered by any other method. So, it is proposed that there is a real relevant physical horizon at the twice the Schwarzschild radius dubbed the holographic information geometric horizon.

A new non-associative algebra for the quantization of strongly interacting fields is proposed. The full set of quantum $(\pm)$associators for the product of three operators is offered. An algorithm for the calculation of some $(\pm)$associators for the product of some four operators is offered. The possible generalization of Hamilton&#39;s equations for a non-associative quantum theory is proposed. Some arguments are given that a non-associative quantum theory can be a fundamental unifying theory.

We study a string theory which is exclusively based on extrinsic curvature action. It is a tensionless string theory because the action reduces to perimeter for the flat Wilson loop. We are able to solve and quantize this high-derivative nonlinear two-dimensional conformal field theory. The absence of conformal anomaly in quantum theory requires that the space-time should be 13-dimensional. We have found that all particles, with arbitrary large spin, are massless. This pure massless spectrum is consistent with the tensionless character of the theory and we speculate that it may describe unbroken phase of standard string theory.

The perturbative leading order open string three-point couplings for the Standard Model with hidden U Sp(6) on fractional D6-branes on T 6 /Z 6 from [1, 2] are computed. Physical Yukawa couplings consisting of holomorphic Wilsonian superpotential terms times a non-holomorphic prefactor involving the corresponding classical open string Kähler metrics are given, and mass terms for all non-chiral matter states are derived. The lepton Yukawa interactions are at leading order flavour diagonal, while the quark sector displays a more intricate pattern of mixings. While N = 2 supersymmetric sectors acquire masses via only two D6-brane displacements-which also provide the hierarchies between up-and down-type Yukawas within one quark or lepton generation-, the remaining vector-like states receive masses via perturbative three-point couplings to some Standard Model singlet fields with vevs along flat directions. Couplings to the hidden sector and messengers for supersymmetry breaking are briefly discussed.

IEEE P1596, the Scalable Coherent Interface (formerly known as SuperBus) is based on experience gained while developing Fastbus (ANSI/IEEE 960-1986, IEC 935), Futurebus (IEEE P896.x) and other modern high-performance buses. SC1 goals include a minimum bandwidth of 1 GByte/sec per processor in multiprocessor systems with thousands of processors; efficient support of a coherent distributed-cache image of distributed shared memory; support for bridges which interface to existing or future buses; and support for inexpensive small rings as well as for general switched interconnections like Banyan, Omega, or crossbar networks. This paper reports the status of the work in progress and suggests some applications in data acquisition and physics.

Neutrino oscillation is a quantum mechanical phenomenon in which neutrino flavor changes spontaneously to another flavor. In the simple two flavor (ν µ , ν e) case, the probability that ν µ changes to ν e is expressed by P νµ→νe = sin 2 2θ sin 2 m 2 2 − m 2 1 4E ν L where E ν is the neutrino energy, L is the distance between the neutrino source and detector, m 1 and m 2 are the neutrino masses of the mass eigenstates and θ is the mixing angle between flavor eigenstates and mass eigenstates.

Charge Coupled Devices (CCDs) have been successfully used in several high energy physics experiments over the past two decades. Their high spatial resolution and thin sensitive layers make them an excellent tool for studying short-lived particles. The Linear Collider Flavour Identification (LCFI) collaboration is developing Column-Parallel CCDs (CPCCDs) for the vertex detector of a future Linear Collider. The CPCCDs can be read out many times faster than standard CCDs, significantly increasing their operating speed. Radiation hardness is an important aspect in the CCD development. Bulk radiation damage in the silicon leads to electron traps and hence to charge transfer inefficiency (CTI). The effects of the two trap levels 0.17 and 0.44 eV are considered. We have extended our Analytic Model to include the effects of the shape of the signal charge packet and the clock voltage on the CTI determination. The CTI values determined with the Analytic Model largely agree with those from a full TCAD simulation. * Presented on behalf of the LCFI Collaboration;

Cabibbo-suppressed charm decays offer a good laboratory for studying weak interactions as they provide a unique window on the physics governing the decay-rate dynamics and CP violation. The branching ratios of the singly Cabibbo-suppressed decays of D0 meson are anomalous since the branching fraction of D0! m mÿ is observed to be suppressed relative to that of D0! K Kÿ by a factor of almost three [1], even though the phase space for the former is larger. The branching ratios of three-body decays of the D0 [2, 3] have larger uncertainties ...

We consider the generalized laws of thermodynamics in massive gravity. Making use of explicit black hole solutions, we devise black hole merger processes in which i) total entropy of the system decreases ii) the zero-temperature extremal black hole is created. Thus, both second and third laws of thermodynamics are violated. In both cases, the violation can be traced back to the presence of negative-mass black holes, which, in turn, is related to the violation of the null energy condition. The violation of the third law of thermodynamics implies, in particular, that a naked singularity may be created as a result of the evolution of a singularity-free state. This may signal a problem in the model, unless the creation of the negative-mass black holes from positive-mass states can be forbidden dynamically or the naked singularity may somehow be resolved in a full quantum theory.

In this Ph. D. Thesis we concentrate on the study of the extension of the AdS/CFT correspondence to theories with less supersymmetry. In particular, we search for the possibility of adding supersymmetric D-branes in type IIB supergravity solutions which are dual to N=1 supersymmetric gauge theories in four dimensions. In the probe approximation we perform a systematic analysis of the possible supersymmetric D-brane configurations in backgrounds dual to N=1 superconformal field theories, firstly in the AdS_5xY^{p,q} solutions and then in their generalisation to the AdS_5xL^{a,b,c} backgrounds. Some checks of the correspondence between D-brane configurations and chiral operators of the dual gauge theory are performed. We also analyse the possible supersymmetric D5-brane configurations dual to defects (of codimension one and two) in N=1 SYM theory in the framework of the Maldacena-Nunez solution. Beyond the probe approximation, we develop techniques in order to take into account the ba...

We present a general approach to incorporate hadronic as well as quark degrees of freedom in a unified approach. This approach implements the correct degrees of freedom at high as well as low temperatures and densities. An effective Polyakov loop field serves as the order parameter for deconfinement. We employ a well-tested hadronic flavor-SU(3) model based on a chirally symmetric formulation that reproduces properties of ground state nuclear matter and yields good descriptions of nuclei and hypernuclei. Excluded volume effects simulating the finite size of the hadrons drive the transition to quarks at high temperatures and densities. We study the phase structure of the model and the transition to the quark gluon plasma and compare results to lattice gauge calculations.

Amplitudes for fermion-fermion, boson-boson and fermion-boson interactions are calculated in the second order of perturbation theory in the Lobachevsky space. An essential ingredient of the model is the Weinberg's 2(2j + 1)− component formalism for describing a particle of spin j. The boson-boson amplitude is then compared with the two-fermion amplitude obtained long ago by Skachkov on the basis of the Hamiltonian formulation of quantum field theory on the mass hyperboloid, p 2 0 − p 2 = M 2 , proposed by Kadyshevsky. The parametrization of the amplitudes by means of the momentum transfer in the Lobachevsky space leads to same spin structures in the expressions of T − matrices for the fermion case and the boson case. However, certain differences are found. Possible physical applications are discussed.

This article reports on the feasibility of testing of the symmetry under reversal in time in a purely leptonic system constituted by positronium atoms using the J-PET detector. The present state of T symmetry tests is discussed with an emphasis on the scarcely explored sector of leptonic systems. Two possible strategies of searching for manifestations of T violation in nonvanishing angular correlations of final state observables in the decay of metastable triplet states of positronium available with J-PET are proposed and discussed. Results of a pilot measurement with J-PET and assessment of its performance in reconstruction of three-photon decays are shown along with an analysis of its impact on the sensitivity of the detector for the determination of T-violation sensitive observables.

The tightening of the constraints on the standard thermal WIMP scenario has forced physicists to propose alternative dark matter (DM) models. One of the most popular alternate explanations of the origin of DM is the non-thermal production of DM via freeze-in. In this scenario the DM never attains thermal equilibrium with the thermal soup because of its feeble coupling strength (∼ 10^-12) with the other particles in the thermal bath and is generally called the Feebly Interacting Massive Particle (FIMP). In this work, we present a gauged U(1)_L_μ-L_τ extension of the Standard Model (SM) which has a scalar FIMP DM candidate and can consistently explain the DM relic density bound. In addition, the spontaneous breaking of the U(1)_L_μ-L_τ gauge symmetry gives an extra massive neutral gauge boson Z_μτ which can explain the muon (g-2) data through its additional one-loop contribution to the process. Lastly, presence of three right-handed neutrinos enable the model to successfully explain t...

AbstractThe work extends the A. Connes’ noncommutative geometry to spaces withgeneric local anisotropy. We apply the E. Cartan’s anholonomic frame approachto geometry models and physical theories and develop the nonlinear connectionformalism for projective modulespaces. Examples of noncommutative generationof anholonomic Riemann, Finsler and Lagrange spaces are analyzed. We alsopresent a research on noncommutative Finsler–gauge theories, generalized Finslergravity and anholonomic (pseudo) Riemann geometry which appear naturally ifanholonomic frames (vierbeins) are defined in the context of string/M–theoryand extra dimension Riemann gravity..Pacs: 02.40.Gh, 02.40.-k, 04.50.+hMSC numbers: 83D05, 46L87, 58B34, 58B20, 53B40, 53C07 Contents 1 Introduction 22 Commutative and Noncommutative Spaces 42.1 Algebras of functions and (non) commutative spaces . . . . . . . . . . . 52.2 Commutative spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.3 Noncommutative spaces . . . . . ....

In this paper we have tried to deduce the possible origin of particle and evolution of their intrinsic properties through spiral dynamics. We consider some of the observations which include exponential mass function of particles following a sequence when fitted on logarithmic potential spiral, inwardly rotating spiral dynamics in Reaction-Diffusion System, the separation of Electron’s Spin-Charge-Orbit into quasi-particles. The paper brings a picture of particles and their Anti Particles in spiral form and explains how the difference in structure varies their properties. It also explains the effects on particles in Accelerator deduced through spiral dynamics.

FLUKA is an integrated particle transport code that has enhanced multigroup low-energy neutron transport capability similar to the well-known MORSE transport code. Gammas are produced in groups but many important individual lines are speciÿcally included, and subsequently transported by the main FLUKA routines which use a modiÿed version of EGS4 for electromagnetic (EM) transport. Recoil protons are also transported by the primary FLUKA transport simulation. The neutron cross-section libraries employed within FLUKA were supplied by Giancarlo Panini (ENEA, Italy) based upon the most recent data from JEF-1, JEF-2.2, ENDF=B-VI, JENDL-3, etc. More than 60 di erent materials are included in the FLUKA databases with temperature ranges including down to cryogenic temperatures. This code has been used extensively to model the neutron environments near high-energy physics experiment shielding. A simulation of the Space Shuttle based upon a spherical aluminum equivalent shielding distribution has been performed with reasonable results. There are good prospects for extending this calculation to a more realistic 3-D geometrical representation of the Shuttle including an accurate representation of its composition, which is an essential ingredient for the improvement of the predictions. A proposed project to develop a combined analysis and simulation package based upon FLUKA and the analysis infrastructure provided by the ROOT software is under active consideration. The code to be developed for this project will be of direct application to the problem of simulating the neutron environment in space, including the albedo e ects.

We applied the wavelet methodology to study the results of the chaotic behavior of the production of particles in relativistic collisions of heavy ions. We use wavelet coherence to analyze the correspondence between theoretical and experimental data. We examined the 1-D phase space of variable (the case -space). We also compared the wavelet coherence values for -space and -space. It was also shown that the values of the wavelet of coherence depend on the values of the parameters p and q. We discussed our new results for the comparison purpose and findings were in the good agreements.

Most scientific data analyses comprise analyzing voluminous data collected from various instruments. Efficient parallel/concurrent algorithms and frameworks are the key to meeting the scalability and performance requirements entailed in such scientific data analyses. The recently introduced MapReduce technique has gained a lot of attention from the scientific community for its applicability in large parallel data analyses. Although there are many evaluations of the MapReduce technique using large textual data collections, there have been only a few evaluations for scientific data analyses. The goals of this paper are twofold. First, we present our experience in applying the MapReduce technique for two scientific data analyses: (i) High Energy Physics data analyses; (ii) Kmeans clustering. Second, we present CGL-MapReduce, a streaming-based MapReduce implementation and compare its performance with Hadoop.

The method of analytic continuation is one of the most powerful tools to circumvent the sign problem in lattice QCD. The present study is part of a larger project which, based on the investigation of QCD-like theories which are free of the sign problem, is aimed at testing the validity of the method of analytic continuation and at improving its predictivity, in view of its application to real QCD. We have shown that a considerable improvement can be achieved if suitable functions are used to interpolate data with imaginary chemical potential. We present results obtained in a theory free of the sign problem such as two-color QCD at finite chemical potential.

In this paper we consider the implications of the "landscape" paradigm for the large scale properties of the universe. The most direct implication of a rich landscape is that our local universe was born in a tunnelling event from a neighboring vacuum. This would imply that we live in an open FRW universe with negative spatial curvature. We argue that the "overshoot" problem, which in other settings would make it difficult to achieve slow roll inflation, actually favors such a cosmology.

Here we formulate two field redefinitions for N = 4 Super Yang-Mills in light cone superspace that generates only MHV vertices in the new Lagrangian. After careful consideration of the S-matrix equivalence theorem, we see that only the canonical transformation gives the MHV Lagrangian that would correspond to the CSW expansion. Being in superspace, it is easier to analyse the

Single dye molecules at cryogenic temperatures display many spectroscopic phenomena known from free atoms and are thus promising candidates for fundamental quantum optical studies. However, the existing techniques for the detection of single molecules have either sacrificed the information on the coherence of the excited state or have been inefficient. Here we show that these problems can be addressed by focusing the excitation light near to the absorption cross section of a molecule. Our detection scheme allows us to explore resonance fluorescence over 9 orders of magnitude of excitation intensity and to separate its coherent and incoherent parts. In the strong excitation regime, we demonstrate the first observation of the Mollow triplet from a single solid-state emitter. Under weak excitation we report the detection of a single molecule with an incident power as faint as 150 attoWatt, paving the way for studying nonlinear effects with only a few photons.

A ten-channel analog switch has been developed as a sample and shape circuit for signals used as inputs to a logarithmic pulse height recording system. The circuit employs a field effect transistor as the switching element. Switching transients are reduced to approximately 2 mV by adding to the gated signal an inverted transient generated by an identical circuit with no signal applied. The circuit is linear to 2% from 3 mV to 10 V.

The 'whispering gallery' effect has been known since ancient times for sound waves in air 1,2 , later in water and more recently for a broad range of electromagnetic waves: radio, optics, Roentgen and so on 3-6. It consists of wave localization near a curved reflecting surface and is expected for waves of various natures, for instance, for atoms 7,8 and neutrons 9. For matter waves, it would include a new feature: a massive particle would be settled in quantum states, with parameters depending on its mass. Here, we present for the first time the quantum whispering-gallery effect for cold neutrons. This phenomenon provides an example of an exactly solvable problem analogous to the 'quantum bouncer' 10 ; it is complementary to the recently discovered gravitationally bound quantum states of neutrons 11. These two phenomena provide a direct demonstration of the weak equivalence principle for a massive particle in a pure quantum state 12. Deeply bound whispering-gallery states are long-living and weakly sensitive to surface potential; highly excited states are short-living and very sensitive to the wall potential shape. Therefore, they are a promising tool for studying fundamental neutron-matter interactions 13-15 , quantum neutron optics and surface physics effects 16-18. The classical whispering-gallery phenomenon can be understood in terms of geometrical optics. Thus, neutron Garland trajectories with a high probability of specular reflection have been observed in curved neutron guides 19 and frequently used in neutron experiments. Elliptical focusing neutron guides using a single reflection are available in commerce. Sound can be reflected in an elliptical chamber from one focus to the other one after 'a single bounce'. A more complex phenomenon consists of wave localization in the vicinity of curved surfaces, also called the whispering-gallery effect. Owing to such localization, the sound can reach a person on the opposite side of a building, or even complete a circle, imitating an 'echo'. Lord Rayleigh explained and described quantitatively this phenomenon in his 'Theory of sound' 1,2. He verified the theory using a whistle as a sound source and burning candles as the sound intensity 'detectors'. Whales are believed to communicate over long distances, profiting from a similar effect in surface layers of sea water. The electromagnetic whispering-gallery waves from radio to light ('glory' or 'heiligenschein') and Roentgen frequencies are of ever-growing interest 3-6 owing to their multiple applications. They are also known as 'Mie scattering' in light scattering from aerosols and in nuclear physics. An optical analogue of a quantum particle bouncing on a hard surface under the influence of gravity or centrifugal potential has been demonstrated recently using a circularly curved optical waveguide 20. In all of these cases, a curved mirror acts as a waveguide; and interference of the waves falling to the mirror and those reflected causes specific stationary whispering-gallery modes. For a material wave in a quantum limit 7-9 , a new feature would appear: radial motion of a massive object would be settled in quantum states, with parameters depending on its mass. At

The main purpose of the report is to provide some argumentation that three seemingly distinct approaches of 1. Giveon, Kutasov and Seiberg (hep-th/9806194); 2. Hemming, Keski-Vakkuri (hep-th/0110252); Maldacena, Ooguri (hep-th/0001053) and 3. I. Bars (hep-th/9503205) can be investigated by applying the mathematical methods of integral geometry on the Lobachevsky plane, developed previously by Gel&#39;fand, Graev and Vilenkin. All these methods can be used for finding the transformations, leaving the Kac-Moody and Virasoro algebras invariant. The near-distance limit of the Conformal Field Theory of the SL(2, R) WZW model of strings on an ADS3 background can also be interpreted in terms of the Lobachevsky Geometry : the non - euclidean distance is conserved and the Lobachevsky formulae for the angle of parallelism is recovered. Some preliminary technique from integral geometry for inverting the modified integral representation for the Kac- Moody algebra has been demonstrated.

We present the mini-proceedings of the workshop on ``Photoproduction at collider energies: from RHIC and HERA to the LHC&#39;&#39; held at the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*, Trento) from January 15 to 19, 2007. The workshop gathered both theorists and experimentalists to discuss the current status of investigations of high-energy photon-induced processes at

Multi-proxy approach was used to reconstruct the environmental conditions of remote lakes in the High Tatra Mountains (Slovakia) over the past few centuries (approximately 500-1000 years). Short sediment cores (*30 cm) taken from three morphologically similar glacial lakes distributed along altitudinal gradient (subalpine to alpine conditions) were analysed for organic matter content (LOI), diatoms and chironomids. Both descriptive and correlative approaches were used for analysing stratigraphical data. Predictive canonical correspondence analysis and co-correspondence analysis were applied to directly relate physical and biological proxies to each other. The relationship between LOI and biotic proxies was inconsistent across groups and lakes. Concordant patterns in diatom and chironomid composition were found in two non-acidified lakes. Common trends in those assemblages indicated major past environmental events such as the Little Ice Age, air pollution and lake acidification. In contrast, no relationship between the composition of diatom and chironomid assemblages was found in the formerly acidified lake, suggesting different responses of assemblages to acidification. While chironomids showed shifts that are attributable to recovery, diatoms assemblage remained relatively stable throughout the uppermost layers of the sediment record. On the other hand, climatic-driven changes in assemblages detected in the deeper layers were more pronounced in diatoms than in chironomids.

We compute the complete set of Feynman Rules producing the Rational Terms of kind R 2 needed to perform any QCD 1-loop calculation. We also explicitly check that in order to account for the entire R 2 contribution, even in case of processes with more than four external legs, only up to four-point vertices are needed. Our results are expressed both in the 't Hooft Veltman regularization scheme and in the Four Dimensional Helicity scheme, using explicit color configurations as well as the color connection language.

All fields of the standard model and gravity are unified as an E8 principal bundle connection. A non-compact real form of the E8 Lie algebra has G2 and F4 subalgebras which break down to strong su(3), electroweak su(2) x u(1), gravitational so(3,1), the frame-Higgs, and three generations of fermions related by triality. The interactions and dynamics of these 1-form and Grassmann valued parts of an E8 superconnection are described by the curvature and action over a four dimensional base manifold.

— In high-energy physics, with the search for ever smaller signals in ever larger data sets, it has become essential to extract a maximum of the available information from the data. Multivariate classification methods based on machine learning techniques have ...

A continuous wavelet analysis is performed for pattern recognition of charged particle emission data in28Si-Ag/Br interaction at 14.5A GeV and in32S-Ag/Br interaction at 200A GeV. Making use of the event-wise local maxima present in the scalograms, we try to identify the collective behavior in multiparticle production, if there is any. For the first time, the wavelet results are compared with a model prediction based on the ultrarelativistic quantum molecular dynamics (UrQMD), where we adopt a charge reassignment algorithm to modify the UrQMD events to mimic the Bose-Einstein type of correlation among identical mesons—a feature known to be the most dominating factor responsible for local cluster formation. Statistically significant deviations between the experiment and the simulation are interpreted in terms of nontrivial dynamics of multiparticle production.

The occurrence of a spacetime singularity indicates the breakdown of Einstein gravitation theory in these extreme regimes. We consider here the singularity issue and various black hole paradoxes at classical and quantum levels. It is pointed out that a possible resolution to these problems could be arrived at by avoiding the formation of trapped surfaces during a continual gravitational collapse. A class of perfect fluid collapse models is constructed which realizes such a possibility. While the pressure could be negative in the interior of the cloud, the weak energy condition is satisfied. The collapsing star radiates away most of its matter as the process of gravitational collapse evolves, so as to avoid the formation of trapped surfaces and the spacetime singularity. The collapsing interior is matched to an exterior which is a generalized Vaidya spacetime to complete the model.

Many condensed matter experiments explore the finite temperature dynamics of systems near quantum critical points. Often, there are no well-defined quasiparticle excitations, and so quantum kinetic equations do not describe the transport properties completely. The theory shows that the transport co-efficients are not proportional to a mean free scattering time (as is the case in the Boltzmann theory of quasiparticles), but are completely determined by the absolute temperature and by equilibrium thermodynamic observables. Recently, explicit solutions of this quantum critical dynamics have become possible via the AdS/CFT duality discovered in string theory. This shows that the quantum critical theory provides a holographic description of the quantum theory of black holes in a negatively curved anti-de Sitter space, and relates its transport co-efficients to properties of the Hawking radiation from the black hole. We review how insights from this connection have led to new results for experimental systems: (i) the vicinity of the superfluid-insulator transition in the presence of an applied magnetic field, and its possible application to measurements of the Nernst effect in the cuprates, (ii) the magnetohydrodynamics of the plasma of Dirac electrons in graphene and the prediction of a hydrodynamic cyclotron resonance. this state, but there is a well-developed theory of the transport properties of the TL liquid. Historically, this theory evolved over several decades of research on quantum many body systems in one dimension. Key in the historical development were exact solutions of model Hamiltonians via the Bethe Ansatz. Insights gained from the structure of excitations in the Bethe Ansatz solutions led to a more general understanding of the low energy excitations of a generic Hamiltonian, and a universal low energy theory of the TL liquid. Thus while the exact solutions were restricted to artificial models, they played a key role in the development of the general theory. Of course, after the fact, with the general theory of the TL liquid before us, we can justify it in its own terms, and largely dispense with reference to the Bethe Ansatz solutions.

Some results about dissipative processes in superfluids are presented. We focus on fermionic superfluidity and restrict our analysis to the contribution of phonons to bulk viscosity, shear viscosity and thermal conductivity. At sufficiently low temperatures phonons give the dominant contribution to the transport coefficients if all the other low energy excitation of the system are gapped. We first consider a system of cold fermionic atoms close to the unitarity limit. Then we turn to the superfluid phase of quark matter that may be realized at high baryonic density.

Geant4 is a very large, highly accurate toolkit for Monte Carlo simulation of particle-matter interaction. It has been applied to high-energy physics, cosmic ray modeling, radiation shields, radiation therapy, mine detection, and other areas. Geant4 is being used to help design some high energy physics experiments (notably CMS and Atlas) to be run on the future large hadron collider: the largest particle collider in the world. The parallelization, ParGeant4, represents a challenge due to the unique characteristics of Geant4: (i) complex object-oriented design; (ii) intrinsic use of templates and abstract classes to be instantiated later by the end user; (iii) large program with many developers; and (iv) frequent releases. The key issue for parallelization is not just how to parallelize "correctly" but also how to parallelize "with minimum effort". In addition, the parallelization should make as few assumptions about the source code as possible, due to the frequent release schedule of Geant4. We use TOP-C (Task Oriented Parallel C/C++) for parallelization and Marshalgen for marshaling/serialization. In some examples on a cluster of 100 nodes yielded a speedup of up to 94.4. The code's portability, scalability and performance are also discussed.