The mini-proceedings of the 17$^{mathrm{th}}$ Meeting of the Working Group on Radiative Corrections and MonteCarlo Generators for Low Energies held in Frascati, 20$^{mathrm{th}}$ - 21$^{mathrm{st}}$ April, are presented. These meetings, started in 20
06, have as aim to bring together experimentalists and theoreticians working in the fields of meson transition form factors, hadronic contributions to the anomalous magnetic moment of the leptons, and the effective fine structure constant. The development of MonteCarlo generators and Radiative Corrections for precision $e^+e^-$ and $tau$-lepton physics are also covered, with emphasis on meson production. Heavy quark masses were covered as well in this edition.
We report on the first observations of $bar{B}^0 to D_1(2430)^0 omega$, $bar{B}^0 to D_1(2420)^0 omega$ and $bar{B}^0 to D^*_2(2460)^0 omega$ decays. The $bar{B}^0 to D^{*+} rho(1450)^-$ decay is also observed. The branching fraction measurements are
based on $(771.6 pm 10.6)times 10^6$ $Bbar{B}$ events collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The fractions of longitudinal polarization of the $D^{**}$ states as well as partial wave fractions of the $D_1(2430)^0$ are obtained. We also set a $90%$ confidence level upper limit for the product of branching fractions of $mathcal{B}(bar{B}^0 to D^{*+} b_1(1235)^-) times mathcal{B}(b_1(1235)^- to omega pi^-)$. The measurements show evidence of nontrivial final-state interaction phases for the $rho$-like amplitudes.
We report a search for $B$ decays to selected final states with the $eta_c$ meson: $B^{pm}to K^{pm}eta_cpi^+pi^-$, $B^{pm}to K^{pm}eta_comega$, $B^{pm}to K^{pm}eta_ceta$ and $B^{pm}to K^{pm}eta_cpi^0$. The analysis is based on $772times 10^6$ $Bbar{B
}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We set 90% confidence level upper limits on the branching fractions of the studied $B$ decay modes, independent of intermediate resonances, in the range $(0.6-5.3)times 10^{-4}$. We also search for molecular-state candidates in the $D^0bar{D}^{*0}-bar{D}^0D^{*0}$, $D^0bar{D}^0+bar{D}^0D^0$ and $D^{*0}bar{D}^{*0}+bar{D}^{*0}D^{*0}$ combinations, neutral partners of the $Z(3900)^{pm}$ and $Z(4020)^{pm}$, and a poorly understood state $X(3915)$ as possible intermediate states in the decay chain, and set 90% confidence level upper limits on the product of branching fractions to the mentioned intermediate states and decay branching fractions of these states in the range $(0.6-6.9)times 10^{-5}$.
The mini-proceedings of the 15th Meeting of the Working Group on Rad. Corrections and MC Generators for Low Energies held in Mainz on April 11, 2014, are presented. These meetings, started in 2006, have as aim to bring together experimentalists and t
heorists working in the fields of meson transition form factors, hadronic contributions to $(g-2)_mu$ and the effective fine structure constant, and development of Monte Carlo generators and Radiative Corrections for precision e+e- and tau physics.
We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophys
ics and cosmology to strongly-coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.
The mini-proceedings of the 14th Meeting of the Working Group on Rad. Corrections and MC Generators for Low Energies held in Frascati on September 13, 2013, as a satellite meeting of the PHIPSI13 conference in Rome, are presented. These meetings, sta
rted in 2006, have as aim to bring together experimentalists and theorists working in the fields of meson transition form factors, hadronic contributions to (g-2)_mu and the effective fine structure constant, and development of MonteCarlo generators and Radiative Corrections for precision e+e- and tau physics.
The mini-proceedings of the Workshop on Meson Transition Form Factors held in Cracow from May 29th to 30th, 2012 introduce the meson transition form factor project with special emphasis on the interrelations between the various form factors (on-shell
, single off-shell, double off-shell). Short summaries of the talks presented at the workshop follow.
We summarize recent developments in heavy quarkonium spectroscopy, relying on previous review articles for the bulk of material available prior to mid-2010. This note is intended as a mini-review to appear in the 2012 Review of Particle Physics published by the Particle Data Group.
We report the results of a study of $B^{pm}to K^{pm}eta_c$ and $B^{pm}to K^{pm}eta_c(2S)$ decays followed by $eta_c$ and $eta_c(2S)$ decays to $(K_SKpi)^0$. The results are obtained from a data sample containing 535 million $Bbar{B}$-meson pairs coll
ected by the Belle experiment at the KEKB $e^+e^-$ collider. We measure the products of the branching fractions ${mathcal B}(B^{pm}to K^{pm}eta_c){mathcal B}(eta_cto K_S K^{pm}pi^{mp})=(26.7pm 1.4(stat)^{+2.9}_{-2.6}(syst)pm 4.9(model))times 10^{-6}$ and ${mathcal B}(B^{pm}to K^{pm}eta_c(2S)){mathcal B}(eta_c(2S)to K_S K^{pm}pi^{mp})=(3.4^{+2.2}_{-1.5}(stat+model)^{+0.5}_{-0.4} syst))times 10^{-6}$. Interference with the non-resonant component leads to significant model uncertainty in the measurement of these product branching fractions. Our analysis accounts for this interference and allows the model uncertainty to be reduced. We also obtain the following charmonia masses and widths: $M(eta_c)=(2985.4pm 1.5(stat)^{+0.5}_{-2.0}(syst))$ MeV/$c^2$, $Gamma(eta_c)=(35.1pm 3.1(stat)^{+1.0}_{-1.6}(syst))$ MeV/$c^2$, $M(eta_c(2S))=(3636.1^{+3.9}_{-4.2}(stat+model)^{+0.7}_{-2.0}(syst))$ MeV/$c^2$, $Gamma(eta_c(2S))=(6.6^{+8.4}_{-5.1}(stat+model)^{+2.6}_{-0.9}(syst))$ MeV/$c^2$.
A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Q
uarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of cbar{c}, bbar{b}, and bbar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.
