Heavy Quarkonia sector in PYTHIA 6.324: tuning, validation and perspectives at LHC(b)

In this note we investigate the impact of the recent insertion of Color Octet Model processes in PYTHIA version 6.324, through a tuning of different PYTHIA parameters, including the low-p$_T$ behaviour. The Non-relativistic QCD parameters have been chosen according to the most recent theoretical calculations and fits to CDF data. This analysis has been mainly focused on J/$\psi$ and $\Upsilon$ prompt production, with a comparison of the Monte Carlo predictions with available data from CDF at Run I and Run II energies. A prediction at the LHC energy, within different acceptance regions (CMS-Atlas and LHCb ones), is also given

Phenomenological Constraints on Extended Quark Sectors

We study the flavor physics in two extensions of the quark sector of the Standard Model (SM): a four generation model and a model with a single vector--like down--type quark (VDQ). In our analysis we take into account the experimental constraints from tree--level charged current processes, rare Kaon decay processes, rare B decay processes, the $Z\to b \bar{b}$ decay, $K$, $B$ and $D$ mass differences, and the CP violating parameters \frac \epsilon^\prime}{\epsilon}, $\epsilon_K$ and $a_{\psi K}$. All the constraints are taken at two sigma. We find bounds on parameters which can be used to represent the New Physics contributions in these models ($\lambda_{t^ \prime}^{bd}$, $\lambda_{t^ \prime}^{bs}$ and $\lambda_{t^ \prime}^{sd}$ in the four--generation model, and $U_{bd}$, $U_{bs}$ and $U_{sd}$ in the VDQ model) due to all the above constraints. In both models the predicted ranges for $a_{SL}$ (the CP asymmetry in semi-leptonic decays), $\Delta M_D$, $B(K^+\to\pi^+ \nu \bar{\nu})$, $B(K_L\to\pi^0 \nu \bar{\nu})$ and $B(K_L\to \mu \bar{\mu})_{SD}$ can be significantly higher than the predictions of the SM, while the allowed ranges for $a_{\psi K}$ and for $\Delta m_{B_S}$ are consistent with the SM prediction.Comment: 22 pages, 5 figures (v3: added a reference, updated a reference, added missing units

The CKM Matrix and The Unitarity Triangle: Another Look

The unitarity triangle can be determined by means of two measurements of its sides or angles. Assuming the same relative errors on the angles $(\alpha,\beta,\gamma)$ and the sides $(R_b,R_t)$, we find that the pairs $(\gamma,\beta)$ and $(\gamma,R_b)$ are most efficient in determining $(\bar\varrho,\bar\eta)$ that describe the apex of the unitarity triangle. They are followed by $(\alpha,\beta)$, $(\alpha,R_b)$, $(R_t,\beta)$, $(R_t,R_b)$ and $(R_b,\beta)$. As the set \vus, \vcb, $R_t$ and $\beta$ appears to be the best candidate for the fundamental set of flavour violating parameters in the coming years, we show various constraints on the CKM matrix in the $(R_t,\beta)$ plane. Using the best available input we determine the universal unitarity triangle for models with minimal flavour violation (MFV) and compare it with the one in the Standard Model. We present allowed ranges for $\sin 2\beta$, $\sin 2\alpha$, $\gamma$, $R_b$, $R_t$ and $\Delta M_s$ within the Standard Model and MFV models. We also update the allowed range for the function $F_{tt}$ that parametrizes various MFV-models.Comment: "published version. few typos corrected, results unchanged

Exploring CP Violation through Correlations in B --> pi K, B_d --> pi^+pi^-, B_s --> K^+K^- Observable Space

We investigate allowed regions in observable space of B --> pi K, B_d --> pi^+pi^- and B_s --> K^+K^- decays, characterizing these modes in the Standard Model. After a discussion of a new kind of contour plots for the $B\to\pi K$ system, we focus on the mixing- induced and direct CP asymmetries of the decays B_d --> pi^+pi^- and B_s--> K^+K^-. Using experimental information on the CP-averaged B_d --> pi^{+/-}K^{+/-} and B_d --> pi^+pi^- branching ratios, the relevant hadronic penguin parameters can be constrained,implying certain allowed regions in observable space. In the case of B_d --> pi^+pi^-, an interesting situation arises now in view of the recent B-factory measurements of CP violation in this channel, allowing us to obtain new constraints on the CKM angle gamma as a function of the B^0_d--\bar{B^0_d} mixing phase phi_d=2beta, which is fixed through A_{CP}^{mix}(B_d --> J/psi K_S) up to a twofold ambiguity. If we assume that A_{CP}^{mix}(B_d --> pi^+pi^-) is positive, as indicated by recent Belle data, and that phi_d is in agreement with the ``indirect'' fits of the unitarity triangle, also the corresponding values for gamma around 60 degrees can be accommodated. On the other hand, for the second solution of phi_d, we obtain a gap around gamma ~ 60 degrees. The allowed region in the space of A_{CP}^{mix}(B_s --> K^+K^-) and A_{CP}^{dir}(B_s --> K^+K^-) is very constrained in the Standard Model, thereby providing a narrow target range for run II of the Tevatron and the experiments of the LHC era.Comment: 34 pages, LaTeX, 12 figures. More detailed introduction and a few Comments added, conclusions unchanged. To appear in Phys. Rev.

CP Violation in a Supersymmetric SO(10) x U(2)_{F} Model

A model based on SUSY SO(10) combined with U(2) family symmetry constructed recently by the authors is generalized to include phases in the mass matrices leading to CP violation. In contrast with the commonly used effective operator approach, $\bar{126}$-dimensional Higgs fields are utilized to construct the Yukawa sector. R-parity symmetry is thus preserved at low energies. The symmetric mass textures arising from the left-right symmetry breaking chain of SO(10) give rise to very good predictions for quark and lepton masses and mixings. The prediction for $\sin 2\beta$ agrees with the average of current bounds from BaBar and Belle. In the neutrino sector, our predictions are in good agreement with results from atmospheric neutrino experiments. Our model favors both the LOW and QVO solutions to the solar neutrino anomaly; the matrix element for neutrinoless double beta decay is highly suppressed. The leptonic analog of the Jarlskog invariant, $J_{CP}^{l}$, is predicted to be of $O(10^{-2})$.Comment: RevTeX4; 7 pages; typos corrected; clarification remarks added; more references added. To appear in Physical Review

Positive Parity Scalar Mesons in the 1-2 GeV Mass Range

Based on the observation that K_0(1430) is lighter than its SU_3 counterpart, a_0(1450), we examine the possibility that these particles, together with f_0(1370), f_0(1500) and f_0(1710), fill a tetraquark recurrence of the sub-GeV 0^{++} nonet mixed with a glueball state. We find the picture to be consistent with the known data about the three f_0 resonances, more than the q-qbar hypothesis. Conventional spin-orbit coupling suggests the q-qbar, P-wave, nonet to lie around 1200 MeV. We review possible experimental indications of a scalar isovector resonance at 1.29 GeV, first observed by OBELIX in p-pbar annihilation.Comment: 12 pages, 9 figures. Extended version. References added. Results and conclusions unchange

Developments in Rare Kaon Decay Physics

We review the current status of the field of rare kaon decays. The study of rare kaon decays has played a key role in the development of the standard model, and the field continues to have significant impact. The two areas of greatest import are the search for physics beyond the standard model and the determination of fundamental standard-model parameters. Due to the exquisite sensitivity of rare kaon decay experiments, searches for new physics can probe very high mass scales. Studies of the k->pnn modes in particular, where the first event has recently been seen, will permit tests of the standard-model picture of quark mixing and CP violation.Comment: One major revision to the text is the branching ratio of KL->ppg, based on a new result from KTeV. Several references were updated, with minor modifications to the text. A total of 48 pages, with 28 figures, in LaTeX; to be published in the Annual Review of Nuclear and Particle Science, Vol. 50, December 200

Open and Hidden Charm Production in 920 GeV Proton-Nucleus Collisions

The HERA-B collaboration has studied the production of charmonium and open charm states in collisions of 920 GeV protons with wire targets of different materials. The acceptance of the HERA-B spectrometer covers negative values of xF up to xF=-0.3 and a broad range in transverse momentum from 0.0 to 4.8 GeV/c. The studies presented in this paper include J/psi differential distributions and the suppression of J/psi production in nuclear media. Furthermore, production cross sections and cross section ratios for open charm mesons are discussed.Comment: 5 pages, 9 figures, to be published in the proceedings of the 6th International Conference on Hyperons, Charm & Beauty Hadrons (BEACH04), Chicago, IL, June 27 - July 3, 200

Analysis of charmonium production at fixed-target experiments in the NRQCD approach

We present an analysis of the existing data on charmonium hadro-production based on non-relativistic QCD (NRQCD) calculations at the next-to-leading order (NLO). All the data on J/psi and psi' production in fixed-target experiments and on pp collisions at low energy are included. We find that the amount of color octet contribution needed to describe the data is about 1/10 of that found at the Tevatron

Inclusive V0V^0 Production Cross Sections from 920 GeV Fixed Target Proton-Nucleus Collisions

Inclusive differential cross sections $d\sigma_{pA}/dx_F$ and $d\sigma_{pA}/dp_t^2$ for the production of \kzeros, \lambdazero, and \antilambda particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to $\sqrt {s} = 41.6$ GeV in the proton-nucleon system. The ratios of differential cross sections \rklpa and \rllpa are measured to be $6.2\pm 0.5$ and $0.66\pm 0.07$, respectively, for \xf $\approx-0.06$. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions $d\sigma_{pA}/dp_t^2$ also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections $\sigma_{pA}$ on the atomic mass $A$ of the target material is discussed, and the deduced cross sections per nucleon $\sigma_{pN}$ are compared with results obtained at other energies.Comment: 17 pages, 7 figures, 5 table