The Strong Interaction at the Collider and Cosmic-Rays Frontiers

First data on inclusive particle production measured in proton–proton collisions at the Large Hadron Collider (LHC) are compared to predictions of various hadron-interaction Monte Carlos (qgsjet, epos and sibyll) used commonly in high-energy cosmic-ray physics. While reasonable overall agreement is found for some of the models, none of them reproduces consistently the ${\sqrt{s}}$ evolution of all the measured observables. We discuss the implications of the new LHC data for the modeling of the non-perturbative and semihard parton dynamics in hadron–hadron and cosmic-rays interactions at the highest energies studied today.     

Magnetic hyperfine field at Cr site in AgCrO2 given by Perturbed angular correlations

This work presents an electric field gradient and magnetic hyperfine field study, in the AgCrO₂ multiferroic with triangular spin lattice. The temperature dependence of the electric field gradient (efg) and magnetic hyperfine field (mhf) at Cr site was studied at isolde via perturbed angular correlation measurements with the ¹¹¹In probe, at room temperature and below the Néel temperature (T?≤?21 K) down to 12 K. The results show the presence of two distinct local environments. One axial symmetric efg with a very low mhf, and a non axially symmetric efg with a much higher one. The temperature dependences of mhf magnitude and of the angle between the mhf and the principle component of the efg are investigated.     

Das kritische Magnetfeld Hc∥ von dünnen supraleitenden Filmen

Thin superconducting films in a surface parallel magnetic field are considered, assuming that the order parameter is constant in space. Without any further restrictions on the film thickness,a, an equation for the critical field is derived. In the clean limit, this equation is valid only in the vicinity of T_c, but in the dirty limit it is valid for all temperatures. Our results, for specular reflection, are identical with those obtained byThompson andBaratoff. But for not too thin films we find essential differences between the results for specular and for diffus reflection. For very thin films (a?v/2πT _c), considered in detail byde Gennes andTinkham and byShapoval, our results are in agreement with those obtained byShapoval. In the opposit limit (a?v/2π T _c), the most essential corrections to the Ginzburg-Landau result obtained byLüders are rederived.     

MC-Simulation of the Transverse Double Spin Asymmetry for RHIC

We give a leading order estimate of the hadronic transverse double spin asymmetry in the Drell-Yan process at RHIC using Sphinx tt,anew polarized version ofthe Monte Carlo Pythia 5.6. We also calculate the statistical error to next to leading order with Pythia 5.7. Both quantities are of the same order if one assumes that the transversity weighted parton distributions equal the helicity weighted ones at some low perturbative scale Q ₀ ² .     

The determination by an independent method ofP k electron capture probabilities in133Ba and139Ce decays gamma decay of133Ba

The electron capture decays of¹³³Ba (10.4 y) and¹³⁹Ce (140 d) were investigated with high resolution Ge(Li) detectors. By x-ray — γ-ray coincidences values of the quantityP _k ω _k ? _k for various transitions in the decay of¹³³Ba and¹³⁹Ce are obtained. The factor ω _k ? _k was measured independently by means ofK-conversion electron-K x-ray coincidences and was then used to determineP _k , theK-capture probability. The independent measurement of the product ω _k ? _k , together with recent accurate values of ω _k , provides a new method for the accurate calibration of semiconductor x-ray detectors. In the decay of¹³⁹Ce, a value ofP _k =0.78±0.03 is found (where the error represents twice the standard deviation) from whichQ _ec =326 _?30 ⁺⁷⁰ keV to the¹³⁹La ground-state is found by use of theory. In¹³³Ba decay, values are found ofP _k 1=0.72±0.04 for theEC transition to the 437 keV level in¹³³Cs,P _k 2=0.80±0.07 to the 384 keV level, and from an independent measurement, the ratioP _k 1/P _k 2=0.87±0.07. From these results the ground-state value ofQ _ec =522 _?10 ⁺²⁰ keV is derived from theory for¹³³Ba decay. The gamma spectrum of¹³³Ba also was remeasured. From the present gamma intensities and previous conversion electron intensities, new values forK-shell conversion coefficients are obtained. Previously reported γ-rays at 35 and 391 keV are not confirmed.     

Simulating spin-\frac{3}{2} particles at colliders

Support for interactions of spin- $\frac{3}{2}$ particles is implemented in the FeynRules and ALOHA packages and tested with the MadGraph 5 and CalcHEP event generators in the context of three phenomenological applications. In the first, we implement a spin- $\frac{3}{2}$ Majorana gravitino field, as in local supersymmetric models, and study gravitino and gluino pair-production. In the second, a spin- $\frac{3}{2}$ Dirac top-quark excitation, inspired from compositeness models, is implemented. We then investigate both top-quark excitation and top-quark pair-production. In the third, a general effective operator for a spin- $\frac{3}{2}$ Dirac quark excitation is implemented, followed by a calculation of the angular distribution of the s-channel production mechanism.     

Spezifischer Energieverlust von schweren Ionen in Aluminium,Silber und Gold

Using a Cf²⁵²-fission source and two semiconductor detectors in 180°-position the specific energy loss of heavy ions in A1-, Ag-, and Au-foils was measured. The agreement with the results ofMoak andBrown, and ofKahn andForgue is better than 15%. The energy loss predicted byLindhard is 10–25% lower than the measured values. A better agreement — especially for absorbers with low atomic numberZ — is achieved by a semiempirical formula proposed byMünzel.     

The nature of [S III]λλ9096, 9532 emitters at z = 1.34 and 1.23

A study of [S iii]λλ9096, 9532 emitters at z = 1.34 and 1.23 is presented using our deep narrow-band H ₂ S 1 (centered at 2.13 μm) imaging survey of the Extended Chandra Deep Field South (ECDFS). We combine our data with multi-wavelength data of ECDFS to build up spectral energy distributions (SEDs) from the U to the K _s-band for emitter candidates selected with strong excess in H ₂ S 1 ? K _s and derive photometric redshifts, line luminosities, stellar masses and extinction. A sample of 14 [S iii] emitters are identified with H ₂ S 1 < 22.8 and K _s < 24.8 (AB) over 381 arcmin² area, having [S iii] line luminosity L _[SIII] =～ 1041.5–42.6 erg s^?1. None of the [S iii] emitters is found to have X-ray counterpart in the deepest Chandra 4Ms observation, suggesting that they are unlikely powered by AGNs. The HST/ACS F606W and HST/WFC3 F160W images show their rest-frame UV and optical morphologies. About half of the [S iii] emitters are mergers and at least one third are disk-type galaxies. Nearly all [S iii] emitters exhibit a prominent Balmer break in their SEDs, indicating the presence of a significant post-starburst component. Taken together, our results imply that both shock heating in post-starburst and photoionization caused by young massive stars are likely to excite strong [S iii] emission lines. We conclude that the [S iii] emitters in our sample are dominated by star-forming galaxies (SFGs) with stellar mass 8.7 < log(M/M _⊙) < 9.9.     

Investigation of the two quasiparticle rotational band at 1172 keV in172Yb and determination of theg R -factor of the 3+ 3 band head

Investigations of the rotational band based on the 3⁺ 3 two quasiparticle state in¹⁷²Yb have shown that some of its properties can be well described by the collective model of Bohr and Mottelson. As a result of these investigations we have derived the ratio (g _k – g _R )/Q _o =? (0.0136 ± 0.0007). The magneticg-factor of the band head has also been determined by an integral angular correlation measurement perturbed by an external magnetic field. As a result we foundg=0.201 ± 0.030. Using this value and our result of (g _k – g _R )/Q _o we have calculated theg _R -factor of the two quasiparticle state asg _R =0.283 ± 0.018 which is out of the errors smaller than theg _R -factor of the ground state rotational band. An analysis of our angular correlation experiments gave for the mixing parameter δ of theK-forbidden 1094 keV intraband transition: δ=? (3.63 _?0.06 ^+0.14 ) in agreement with the results of other authors.     

PENTATRAP: a novel cryogenic multi-Penning-trap experiment for high-precision mass measurements on highly charged ions

The novel five-Penning-trap mass spectrometer Pentatrap is developed at the Max-Planck-Institut für Kernphysik (MPIK), Heidelberg. Ions of interest are long-lived highly charged nuclides up to bare uranium. Pentatrap aims for an accuracy of a few parts in 10¹² for mass ratios of mass doublets. A physics program for Pentatrap includes Q-value measurements of β-transitions relevant for neutrino physics, stringent tests of quantum electrodynamics in the regime of extreme electric fields, and a test of special relativity. Main features of Pentatrap are an access to a source of highly charged ions, a multi-trap configuration, simultaneous measurements of frequencies, a continuous precise monitoring of magnetic field fluctuations, a fast exchange between different ions, and a highly sensitive cryogenic non-destructive detection system. This article gives a motivation for the new mass spectrometer Pentatrap, presents its experimental setup, and describes the present status.     

Exact generalized Fokker-Planck equation for arbitrary dissipative and nondissipative quantum-systems

We start from a density matrix equation in its most general form. It comprises the action of external fields on the system, internal interactions, as well as the action of dissipative mechanisms (heat-baths or reservoirs), which may be Markoffian or non-Markoffian. We then define a distribution function of a type introduced previously byHaken, Risken, Weidlich for atoms. This distribution function,f, which is now formulated quite generally with aid of projection operators,P _ik , establishes a connection between theP _ik 's and classical variablesv _ik . By means off it is possible to exactly calculate all quantum mechanical expectation values by purec-number procedures. If the basic density matrix equation is Markoffian, it is even possible to calculate all time-ordered multitime averages byc-number procedures usingf, as had been demonstrated byHaken, Risken andWeidlich. In the present paper we derive in an explicit way an exactc-number partial differential equation forf. It contains derivatives of arbitrarily high order. In important classes of problems, it can be reduced to an ordinary FokkerPlanck equation, however. Our new equation has many applications, e.g. in the quantum theory of lasers, nonlinear quantum optics, spinresonance, and spin-wave-theory, as will be demonstrated in forthcoming papers. We wish to thank Prof. W.Weidlich and Dipl. Phys. H.Vollmer for several valuable discussions. In addition, H.Vollmer has kindly checked our calculations.     

Complete mass spectra ofq\bar q andQ\bar q mesons with improved Bethe-Salpeter dynamics of confinementmesons with improved Bethe-Salpeter dynamics of confinement

The Bethe-Salpeter (bs) dynamics of harmonic confinement developed byanm and collaborators over the last three years and already applied with considerable experimental success to various hadron spectra and coupling structures has been significantly improved through (i) a more exact treatment of a certain momentum-dependent operator \(\hat Q_q \) appearing in thebs equation, using the techniques of SO (2, 1) Lie algebra, and (ii) a sharpened definition of theqcd Coulomb term, so as to yield unambiguous values for different flavour sectors. The resulting mass spectra of light \((q\bar q)\) meson towers and semi-heavy \((Q\bar q)\) quarkonia which are most sensitive to the improved treatment of \(\hat Q_q \) , reveal excellent agreement with experiment, one in which only slight changes in the reduced spring constant \((\tilde \omega )\) and quark masses (m _q ) over the earlier parametrizations are involved. These changes are however found to have a negligible effect on the (already good) numerical values of the other predictions (electroweak and pionic couplings) depending on the \(q\bar q\) andqqq wave functions. A critical assessment of the strong and weak points of this method is madevis-a-vis other related approaches.     

Polynomial behaviour of scattering amplitudes at fixed momentum transfer in theories with local observables

It is shown that, in theories of exactly localized observables, of the type proposed byAraki andHaag, the reaction amplitude for two particles giving two particles is polynomially bounded ins for fixed momentum transfert<0. The proof does not need observables localized in space-time regions of arbitrarily small volume, but uses relativistic invariance in an essential way. It is given for the case of spinless neutral particles, but is easily extendable to all cases of charge and spin. The proof can also be generalized to the case of particles described by regularized products $$\int {\varphi (x_1 ,..., x_n ) \phi _1 } (x - x_1 ) ... \phi _n (x - x_n )dx_1 ...dx_n $$ ofWightman orJaffe fields.     

Determination of relaxation times for iron ions from Mössbauer data

An analysis is made of the experimental results ofBruckner et al., in terms of the relaxation model ofvan der Woude andDekker, and a comparison is made with Wegener's analysis. The two approaches lead in principle to relaxation parameters independent ofH/T and a discrepancy reported byWegener does not exist.     

Isotope shift calculations for open-shell atoms and ions: an extension to the RATIP program

During the past decade, the Ratip program has been found useful for calculating a variety of atomic properties, including energies, transition probabilities, Auger parameters as well as a number of excitation, ionization and capture cross sections for processes with a single electron in the continuum. Recently, in addition, this suite of programs was extended to predict also the isotope shift and hyperfine parameters of open-shell atoms and ions. Here, we review the latest developments of the Ratip program with emphasis on the specific mass-shift M ^sms and field-shift F parameters. Detailed computations for these parameters have been carried out especially for the $4s\;^2S_{1/2} - 4p\;^2P_{1/2,3/2}$ transitions at ~ 397 nm of singly-charged Ca^?+? ions and are compared with available data from the literature.     

Decay energy of183Re→183W

The electron capture decay energy of¹⁸³Re has been determined from the fraction ofK-capture in the transition to the 453.08 keV level in¹⁸³W by delayed coincidences. From this value the total decay energy from₁₈₃Re→¹⁸³W is obtained to beQ=555 _?7 ⁺⁹ keV according to the theory ofBrysk andRose with corrections ofBahcall. The resulting logft values and consequences for the decay scheme are discussed.     

Heat Conduction and Entropy Production in Anharmonic Crystals with Self-Consistent Stochastic Reservoirs

We investigate a class of anharmonic crystals in d dimensions, d≥1, coupled to both external and internal heat baths of the Ornstein-Uhlenbeck type. The external heat baths, applied at the boundaries in the 1-direction, are at specified, unequal, temperatures T _l and T _r . The temperatures of the internal baths are determined in a self-consistent way by the requirement that there be no net energy exchange with the system in the non-equilibrium stationary state (NESS). We prove the existence of such a stationary self-consistent profile of temperatures for a finite system and show that it minimizes the entropy production to leading order in (T _l ?T _r ). In the NESS the heat conductivity κ is defined as the heat flux per unit area divided by the length of the system and (T _l ?T _r ). In the limit when the temperatures of the external reservoirs go to the same temperature T, κ(T) is given by the Green-Kubo formula, evaluated in an equilibrium system coupled to reservoirs all having the temperature T. This κ(T) remains bounded as the size of the system goes to infinity. We also show that the corresponding infinite system Green-Kubo formula yields a finite result. Stronger results are obtained under the assumption that the self-consistent profile remains bounded.     

MCPLOTS: a particle physics resource based on volunteer computing

The mcplots.cern.ch web site (mcplots) provides a simple online repository of plots made with high-energy-physics event generators, comparing them to a wide variety of experimental data. The repository is based on the hepdata online database of experimental results and on the rivet Monte Carlo analysis tool. The repository is continually updated and relies on computing power donated by volunteers, via the lhc@home 2.0 platform.     

Infrared and raman studies of some naphthols

Vibrational spectra of α-naphthol,β-naphthol andβ-naphthol-OD have been recorded in the solid and solution phases. A number of bands, common to all the three compounds, have been correlated with earlier naphthalene assignments and an attempt has been made to identify certain frequencies with vibrational modes that are centred in the substituentsOH andOD. TheC _s symmetry is assumed for each molecule.     

Paraelektrische und paraelastische Umorientierung von Amidionen in KCl,KBr und KJ

Energy loss distributions of electrons with initial kinetic energies of 1.52, 2.65 and 3.66 MeV were measured after penetration through Al, Cu, Ag and Au targets with thicknesses ranging from 0.2 to 0.7 g/cm². The most probable energy lossW and the widthB of the distributions were compared with theoretical results. Fair agreement is obtained forW if the pathlength distribution due to multiple scattering of the electrons in the target is taken into account. This pathlength distribution was obtained by a slight modification ofYang's formula. ForB a discrepancy remained especially for the highZ materials which is probably due to an underestimation of the bremsstrahlungbroadening in the theory ofBlunck andWestphal for energy loss distributions.