Search

Most signatures of new physics in colliders have been studied so far on the transverse plane with respect to the beam direction. In this work however we study the impact of a hidden sector beyond the Standard Model (SM) on inclusive (pseudo)rapidity correlations and moments of the multiplicity distributions, with special emphasis in the LHC results., Comment: Presentation given at ICHEP 2014 Valencia

In this work we estimate the helicity suppressed decay rates of $\eta_b$ resonances into baryon pairs due to instanton-induced effects by rescaling the corresponding partial widths of the experimentally measured branching ratios for the $\eta_c(1S) \to p\bar{p}$ and $\eta_c(1S) \to \Lambda\bar(\Lambda)$ decay modes. Thus we point out that both $\eta_b(1S) \to p\bar{p}$ and $\eta_b(1S) \to \Lambda\bar(\Lambda)$ channels could be detected at a Super B factory and LHC experiments. Furthermore, we examine related instanton-induced effects on WIMP scattering off nuclei concluding, albeit with large uncertainties, that they might enhance the spin-dependent cross section for a light pseudoscalar Higgs boson mediator, thereby inducing a dependence on the momentum transfer to the recoling nucleus., Comment: Presented at Xth Quark Confinement and the Hadron Spectrum Conference, Garching, Munich, October 2012. 8 pages with 4 figures

Motivated by the Goldbach conjecture in Number Theory and the abelian bosonization mechanism on a cylindrical two-dimensional spacetime we study the reconstruction of a real scalar field as a product of two real fermion (so-called \textit{prime}) fields whose Fourier expansion exclusively contains prime modes. We undertake the canonical quantization of such prime fields and construct the corresponding Fock space by introducing creation operators $b_{p}^{\dag}$ --labeled by prime numbers $p$-- acting on the vacuum. The analysis of our model, based on the standard rules of quantum field theory and the assumption of the Riemann hypothesis, allow us to prove that the theory is not renormalizable. We also comment on the potential consequences of this result concerning the validity or breakdown of the Goldbach conjecture for large integer numbers., Comment: 20 pages in A4 format, 2 figures

We explore a scenario in the Next-to-Minimal-Supersymmetric-Standard-Model (NMSSM) with both a light O(10) GeV neutralino and a CP-odd Higgs boson with significant coupling to down-type fermions, evading all current B physics, LEP and WMAP bounds. Motivated by a possible slight lepton universality breaking hinted in Upsilon decays, we consider the effect of the mixing of eta(b) resonances with the pseudoscalar Higgs on the spin-dependent scattering neutralino cross section off nucleons. We conclude that this mechanism could be relevant provided that non-perturbative effects enhance the effective eta(b)-nucleon coupling, taking over velocity/q^2 suppression factors, perhaps giving a new insight into the current controversial situation concerning direct search experiments of dark matter., Comment: We have incorporated a discussion on instanton-induced effects as a possible non-perturbative contribution to WIMP scattering off nuclei. 6 pages, 2 figures

Given a Lie algebra $L$ graded by a group $G$, if $L$ is does not contain orthogonal graded ideals and $G$ is generated by the support of $L$, then $G$ is an abelian group.

In this paper, we present a more detailed version of our previous work for three-particle correlations in quark and gluon jets [1]. We give theoretical results for this observable in the double logarithmic approximation and the modified leading logarithmic approximation. In both resummation schemes, we use the formalism of the generating functional and solve the evolution equations analytically from the steepest descent evaluation of the one-particle distribution. In addition, in this paper we include predictions beyond the limiting spectrum approximation and study this observable near the hump of the single inclusive distribution. We thus provide a further test of the local parton hadron duality (LPHD) and make predictions for the LHC. The computation of higher rank correlators is presented in the double logarithmic approximation and shown to be rather cumbersome., Comment: 34 pages and 14 figures

Three-particle correlations in quark and gluon jets are computed for the first time in perturbative QCD. We give results in the double logarithmic approximation and the modified leading logarithmic approximation. In both resummation schemes, we use the formalism of the generating functional and solve the evolution equations analytically from the steepest descent evaluation of the one-particle distribution. We thus provide a further test of the local parton hadron duality and make predictions for the LHC., Comment: 9 pages and 5 figures. Version published by Physical Review D with reference: Phys. Rev. D 84, 034015 (2011). Two more figures and one section added

The after-dinner talk has by now become a tradition of this Conference series on Quark Confinement and the Hadron Spectrum. On this occasion, I have tried to combine a free-style and (hopefully) amusing presentation with deep questions of physics especially connected with the dynamics of strong interaction. To this end some masterpieces of classical music (by Beethoven, Mozart, Dvorak, Stravinsky ...) and pop music (by Bob Dylan, Eric Clapton) were employed to illustrate certain aspects of physics. By no means was this presentation (nor this paper) intended as a comprehensive review of the different topics examined during the Conference, but rather a call for further thinking on the sinergy of different branches of physics and the excitement of foreseen discoveries in a not too distant future., Comment: 6 pages, 8 figures, After-dinner talk given at the IX Conference on Quark Confinement and the Hadron Structure, Madrid, August 30th to September 3rd 2010

After inserting the heavy quark mass dependence into QCD partonic evolution equations, we determine the mean charged hadron multiplicity and second multiplicity correlators of jets produced in high energy collisions. We thereby extend the so-called dead cone effect to the phenomenology of multiparticle production in QCD jets and find that the average multiplicity of heavy-quark initiated jets decreases significantly as compared to the massless case, even taking into account the weak decay products of the leading primary quark. We emphasize the relevance of our study as a complementary check of $b$-tagging techniques at hadron colliders like the Tevatron and the LHC., Comment: Version revised, accepted for publication in JHEP, 21 pages and 7 figures

In two recent papers (arXiv:1002.1971 [hep-ph] and arXiv:0911.2460 [hep-ph]) Dermisek and Gunion provide new constraints on a light CP-odd Higgs boson in the framework of the NMSSM (or similar models) based on experimental data from LEP, CLEO, BaBar and CDF experiments. In this brief comment we argue that special care is still needed inside a narrow mass window where mixing with $\eta_b$ resonances below $B\bar{B}$ can occur. We also stress that observables testing lepton universality and a possible distorsion of the bottomonium mass spectrum can provide an alternative analysis at (Super) B-factories in the search of such an elusive light pseudoscalar Higgs-like object., Comment: 2 pages, 3 eps figures, references and comments added

The study of multiparticle dynamics in hadron-hadron collisions at Tevatron and LHC could provide useful information on new physics in addition to the expected signatures on the transverse plane. We suggest that an analysis of inclusive correlations between emitted particles in $pp$ inelastic collisions, and factorial moments of multiplicity distributions, may be helpful in uncovering (un)particles from Hidden Sectors, using underlying events tagged by hard products like high $p_T$ leptons and photons, and applying stringent selection criteria like event shape variables, etc, Comment: 4 pages, 2 figs, Talk given at SUSY09, Northeastern University, Boston June 2009

The mass of the eta_b(1S), measured recently by BABAR, is significantly lower than expected from QCD predictions for the Upsilon(1S) - eta_b(1S) hyperfine splitting. We suggest that the observed eta_b(1S) mass is shifted downwards due to a mixing with a CP-odd Higgs scalar A with a mass m_A in the range 9.4 - 10.5 GeV compatible with LEP, CLEO and BABAR constraints. We determine the resulting predictions for the spectrum of the eta_b(nS) - A system and the branching ratios into tau^+ tau^- as functions of m_A., Comment: 4 pages, 4 figures, submitted to PRL, misprint corrected

Most signatures of new physics have been studied on the transverse plane with respect to the beam direction at the LHC where background is much reduced. In this paper we propose the analysis of inclusive longitudinal (pseudo)rapidity correlations among final-state (charged) particles in order to search for (un)particles belonging to a Hidden Sector beyond the Standard Model, using a selected sample of p-p minimum bias events (applying appropriate off-line cuts on events based on, e.g., minijets, high-multiplicity, event shape variables, high-pT leptons and photons, etc) collected at the early running of the LHC. To this aim, we examine inclusive and semi-inclusive two-particle correlation functions, forward-backward correlations, and factorial moments of the multiplicity distribution, without resorting to any particular model but under very general (though simplifying) assumptions. Finally, motivated by some analysis techniques employed in the search for Quark-Gluon-Plasma in heavy-ion collisions, we investigate the impact of such intermediate (un)particle stuff on the (multi)fractality of parton cascades in p-p collisions, by means of a Levy stable law description and a Ginzburg-Landau model of phase transitions. Results from our preliminary study seem encouraging for possible dedicated analyses at the LHC and Tevatron experiments., Comment: 36 pages, 6 figures. New references and a new section on Glasma physics have been added

We study possible effects of a light CP-odd Higgs boson on radiative Upsilon decays in the Next-to-Minimal Supersymmetric Standard Model. Recent constraints from CLEO on radiative Upsilon(1S) decays are translated into constraints on the parameter space of CP-odd Higgs boson masses and couplings, and compared to constraints from B physics and the muon anomalous magnetic moment. Possible Higgs - eta_b(nS) mixing effects are discussed, notably in the light of the recent measurement of the eta_b(1S) mass by Babar: The somewhat large Upsilon(1S) - eta_b(1S) hyperfine splitting could easily be explained by the presence of a CP-odd Higgs boson with a mass in the range 9.4 - 10.5 GeV. Then, tests of lepton universality in inclusive radiative Upsilon decays can provide a visible signal in forthcoming experimental data., Comment: 20 pages, 11 Figs, references corrected

We examine the electronic width ratios of Upsilon resonances below the BBbar threshold by means of an effective (Cornell-type) QCD potential incorporating 1/m_b corrections obtained from a prior fit to the bottomonium spectrum. From our analysis we conclude that the Upsilon(2S) and Upsilon(3S) states should belong to the strong-coupling (nonperturbative) regime while the Upsilon(1S) state should belong to the weak-coupling (perturbative) regime, in agreement with a previous study based on radiative decays., Comment: 8 pages

This paper presents the basics of the QQ-onia package, a software based upon the Numerov method which can be used to solve the Schrodinger radial equation using a suitable potential V(r) for the heavy quarkonium system. This package also allows the analysis of relevant properties of those resonances such as the wave functions at the origin, their corresponding derivatives for l \neq 0 states, typical heavy quark velocities, and mean square radii. Besides, it includes a tool to analize the spin-dependent contributions to the heavy quarkonia spectrum, providing the hyperfine splittings, as well as the nPJ energy levels. Finally, a simple software implemented in QQ-onia to compute E1 transition rates is presented., Comment: 30 pages, 3 figures, a new section on spin-dependent terms in the potential has been added

A light non-standard Higgs boson decaying mainly into $\tau^+\tau^-$ has not been yet ruled out by LEP searches in several scenarios. We verify that, in the context of the Next-to-Minimal-Supersymmetric Standard Model, a low-mass CP-odd (mostly but not completely singlet-like) Higgs boson can couple strongly enough to down-type fermions to be detected in radiative $\Upsilon$ decays into tauonic pairs at a high-luminosity B factory. Possible spectroscopic effects of a mixing with $\eta_b$ resonances are also analyzed, Comment: Latex, 4 pages, 4 figures. Submitted for the SUSY07 proceedings

Several scenarios beyond the minimal extension of the Standard Model still allow light non-standard Higgs bosons evading LEP bounds. We examine the mixing between a light CP-odd Higgs boson and $\eta_b$ states and its implications on a slight (but observable) lepton universality breaking in Upsilon decays which could be measured at the percent level at a (Super) B factory., Comment: 9 pages, 7 figures

We present a proposal for detecting new physics at a B-factory running at the $\Upsilon(3S)$ resonance by testing lepton universality to the few percent level in the leptonic decays of the $\Upsilon(1S)$ and $\Upsilon(2S)$ resonances tagged by the dipion in the chain decay: $\Upsilon(3S) \to pi^+\pi^-\Upsilon(1S,2S)$; $\Upsilon(1S,2S) \to \ell^+\ell^-$, $\ell=e,\mu,\tau$., Comment: 10 pages, 2 figures, Contributed paper to BNM2006 Workshop, September 13-14, 2006, KEK

Heavy quarkonium decays can be used to search for New Physics beyond the Standard Model. In particular, a light Higgs boson could induce a slight (but observable) lepton universality breaking in Upsilon decays. In fact, current experimental data from CLEO presented in this Conference seem to point out to this direction within experimental accuracy. Moreover, LEP constraints on a light Higgs mass can be evaded by different models (like MSSM with a CPV Higgs sector) as shown in this Conference. We also consider spectroscopic consequences stemming from a possible mixing between Higgs and bottomonium states leading to discrepancies with the SM expectations (e.g. hyperfine splittings)., Comment: 4 pages, 1 eps figure, talk given at International Europhysics Conference on HEP, July 21st-27th 2005, Lisboa

A non-standard CP-odd Higgs boson could induce a slight (but observable) lepton universality breaking in Upsilon leptonic decays. Moreover, mixing between such a pseudoscalar Higgs boson and $\eta_b$ states might shift their mass levels, thereby modifying the values of the $M_{\Upsilon(nS)}-M_{\eta_b(nS)}$ hyperfine spplitings predicted in the standard model. Besides, $\eta_b$ resonances could be broader than expected with potentially negative consequences for discovery in both $e^+e^-$ and hadron colliders. A scenario with a CP violating Higgs sector is also considered. Finally, further strategies to search for a light Higgs particle in bottomonium decays are outlined., Comment: LaTeX, 10 pages, 1 EPS figure