Status report on TAUOLA, its environment, and its applications

The status of the Monte Carlo programs for the simulation of the tau-lepton production and decay in high energy accelerator experiments is reviewed. In particular, the status of the following packages is discussed: (i) TAUOLA for tau-lepton decay and PHOTOS for radiative corrections in decays, (ii) MC-TESTER for universal tests of the Monte Carlo programs describing particle decays, (iii) KORALB, KORALZ, KKMC packages for tau-pair production in e+e- collisions, and (iv) universal interface of TAUOLA for the decay of tau-leptons produced by ``any'' generator.Comment: Talk at the Seventh International Workshop on Tau Lepton Physics (TAU02), Santa Cruz, Ca, USA, Sept 2002, 5 pages, LaTeX, 4 eps/ps figure

{\L}S condition for filled Julia sets in C\mathbb{C}

In this article, we derive an inequality of {\L}ojasiewicz-Siciak type for certain sets arising in the context of the complex dynamics in dimension 1. More precisely, if we denote by $dist$ the euclidian distance in $\mathbb{C}$, we show that the Green function $G_K$ of the filled Julia set $K$ of a polynomial such that $\mathring{K}\neq \emptyset$ satisfies the so-called {\L}S condition $\displaystyle G_A\geq c\cdot dist(\cdot, K)^{c'}$ in a neighborhood of $K$, for some constants $c,c'>0$. Relatively few examples of compact sets satisfying the {\L}S condition are known. Our result highlights an interesting class of compact sets fulfilling this condition. The fact that filled Julia sets satisfy the {\L}S condition may seem surprising, since they are in general very irregular. In order to prove our main result, we define and study the set of obstruction points to the {\L}S condition. We also prove, in dimension $n\geq 1$, that for a polynomially convex and L-regular compact set of non empty interior, these obstruction points are rare, in a sense which will be specified

Measuring the Higgs boson parity at a Linear Collider using the tau impact parameter and tau --> rho nu decay

We demonstrate that a measurement of the impact parameter in one-prong tau decay can be useful for the determination of the Higgs boson parity in the H/A --> tau tau; tau --> rho nu decay chain. We have estimated that for a detection set-up such as TESLA, use of the information from the tau impact parameter can improve the significance of the measurement of the parity of the Standard Model 120 GeV Higgs boson to 4.5 sigma, and in general by factor of about 1.5 with respect to the method where this information is not used. We also show that the variation in the assumption on the precision of the measurement of the impact parameter and/or pi's momenta does not affect the sensitivity of the method. This is because the method remains limited by the type of twofold ambiguity in reconstructing the tau momentum.Comment: 12 pages, 12 figures, LaTe

Measuring the Higgs boson's parity using tau --> rho nu

We present a very promising method for a measurement of the Higgs boson parity using the H/A -> tau^+ tau^- --> rho^+ nu rho^- nu --> pi^+ pi^0 nu pi^- pi^0 nu decay chain. The method is both model independent and independent of the Higgs production mechanism. Angular distributions of the tau decay products which are sensitive to the Higgs boson parity are defined and are found to be measurable using typical properties of a future detector for an e^+ e^- linear collider. The prospects for the measurement of the parity of a Higgs boson with a mass of 120 GeV are quantified for the case of e^+ e^- collisons of 500 GeV center of mass energy with an integrated luminosity of 500 fb^-1. The Standard Model Higgsstrahlung production process is used as an example.Comment: 10 pages, 4 figures, LaTeX, version of Phys. Lett.

Observables with tau leptons at LHC and LC structure of event records and Monte Carlo Algorithms

In the present report, let us adress the issues related to simulation of decays for particle embodied in full production and decay chains of Monte Carlo programs set-up for experiments such as at LHC or LC. Both technical issues related to the way how the events may be stored in event records and issues related to physics (in particular non-factorizable correlations of the Einstein-Rosen-Podolsky type) will be reviewed on the basis of practical examples. We will limit our discussion to the case of tau lepton and W boson decays, but similar problems (and solutions) may arise also in case of simulation for other intermediate states or particles. Examples related to construction of physics observables will be also given. In particular the method of measuring the CP parity properties of the h-tau-tau coupling at LC will be explained.Comment: 5 pages, 3 Postscript figures, uses espcrc2.sty, Presented at IX Workshop on A C A T in Physics Research, December 1-5, 2003, KEK, Tsukuba, Japa

Exclusive processes in proton-proton collisions with the CMS experiment at the LHC

We present the recent measurements of exclusive processes performed in the CMS experiment at the LHC using data collected at a centre of mass energy of 7 TeV. These measurements include the double-pomeron production of photon pairs, the two-photon production of leptons pairs, and the previously undetected two-photon production of W boson pairs. While in case of the two first processes that enables to set limits on production cross-section, in the later case it provides also stringent limits on the anomalous quartic gauge couplings.Comment: Presented at the Low x workshop, May 30 - June 4 2013, Rehovot and Eilat, Israe

The method to determine the CP nature of Higgs bosons from decays to tau leptons at LC

We demonstrate how the transverse tau tau spin correlations can be used to determine whether a decaying Higgs boson is a mixed CP eigenstate, thereby directly probe the presence of CP violation in the neutral Higgs boson sector. We investigate the subsequent decay chain H --> tau+ tau- --> rho+ nu rho- nu --> pi+ pi0 nu pi- pi0 nu. The prospects for the measurement of the pseudoscalar admixture in the H-tau-tau coupling to a Standard Model Higgs boson with a mass of 120 GeV are quantified for the case of e+e- collisions at 350 GeV center-of-mass energy and 1 ab^{-1} integrated luminosity. The Standard Model Higgsstrahlung production process is used as an example.Comment: 9 pages, 4 figure, Presented at the XXVII International Conference of Theoretical Physics, Matter To The Deepest, Ustron, Poland, 15-21 September 200