52 research outputs found
We must know. We will know
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 201
A heuristic study of the distribution of primes in short and not-so-short intervals
A numerical study on the distributions of primes in short intervals of length
over the natural numbers is presented. Based on Cram\'er's model in
Number Theory, we obtain a heuristic expression applicable when
but , providing support to the Montgomery and Soundararajan conjecture
on the variance of the prime distribution at this scale.Comment: 8 pages, 6 figure
Searching for hidden sectors in multiparticle production at the LHC
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 Valenci
The ridge effect and three-particle correlations
Pseudorapidity and azimuthal three-particle correlations are studied based on
a correlated-cluster model of multiparticle production. The model provides a
common framework for correlations in proton-proton and heavy-ion collisions
allowing easy comparison with the measurements. It is shown that azimuthal
cluster correlations are definitely required in order to understand
three-particle correlations in the near-side ridge effect. This is similar to
the explanation of the ridge phenomenon found in our previous analysis of
two-particle correlations and generalizes the model to higher-order
correlations.Comment: 16 pages, 7 figures. arXiv admin note: text overlap with
arXiv:1610.0640
Three-particle correlations in QCD jets and beyond
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 figure
Observable imprints of primordial gravitational waves on the temperature anisotropies of the Cosmic Microwave Background
We examine the contribution of tensor modes, in addition to the dominant
scalar ones, on the temperature anisotropies of the cosmic microwave background
(CMB). To this end, we analyze in detail the temperature two-point angular
correlation function from the Planck 2018 dataset, focusing on
large angles () corresponding to small
multipoles. A hierarchical set of infrared cutoffs are naturally introduced to
the scalar and tensor power spectra of the CMB by invoking an extra
Kaluza-Klein dimension compactifying at about the GUT scale between the Planck
epoch and the start of inflation. We associate this set of lower scalar and
tensor cutoffs with the parity of the multipole expansion of the
function. By fitting the Planck 2018 data we compute the multipole coefficients
thereby reproducing the well-known odd-parity preference in angular
correlations seen by all three satellite missions COBE, WMAP and Planck. Our
fits improve significantly once tensor modes are included in the analysis,
hence providing a hint of the imprints of primordial gravitational waves on the
temperature correlations observed in the CMB today. To conclude we suggest a
relationship between, on the one hand, the lack of (positive) large-angle
correlations and the odd-parity dominance in the CMB and, on the other hand,
the effect of primordial gravitational waves on the CMB temperature
anisotropies.Comment: 12 pages, 2 figure
Non-perturbative effects in WIMP scattering off nuclei in the NMSSM
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 figure
Three-particle correlations in QCD parton showers
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
adde
Bottomonium spectroscopy with mixing of eta_b states and a light CP-odd Higgs
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 correcte
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