Casimir scaling, glueballs, and hybrid gluelumps

Assuming that the Casimir scaling hypothesis is well verified in QCD, masses of glueballs andhybrid gluelumps (gluon attached to a point-like

Casimir scaling, glueballs and hybrid gluelumps

Assuming that the Casimir scaling hypothesis is well verified in QCD, masses of glueballs and hybrid gluelumps (gluon with a point-like $c\bar c$ pair) are computed within the rotating string formalism. In our model, two gluons are attached by an adjoint string in a glueball while the gluon and the colour octet $c\bar c$ pair are attached by two fundamental strings in a hybrid gluelump. Masses for such exotic hadrons are computed with very few free parameters. These predictions can serve as a guide for experimental searches. In particular, the ground state glueballs lie on a Regge trajectory and the lightest $2^{++}$ state has a mass compatible with some experimental candidates.Comment: 3 figure

Assessing the WiFi offloading benefit on both service performance and EMF exposure in urban areas

In this paper we assess the benefit of WiFi offloading over dense urban scenarios in terms of both Quality of Service (QoS) and Electromagnetic Field (EMF) exposure. This study relies on results obtained with two complementary simulation platforms: a two-tier dynamic system-level simulator and a 3D coverage-based simulator. Outputs are usual service coverage key performance indicators, handover probability statistics, as well as common and innovative metrics for EMF exposure characterization that jointly take into account the contributions from the base-station and the User-Equipment (UE) transmissions. The main outcome is that, for elastic services, the best QoS and minimum global EMF exposure are jointly achieved with maximum WiFi offloading.This paper reports work undertaken in the context of the FP7 project LEXNET (GA nº 318273). Ramón Agüero also acknowledges the Spanish Government for the project “Connectivity as a Service: Access for the Internet of the Future”, COSAIF (TEC2012-38574-C02-02)

Optimal dosimeter deployment into a smart city IoT platform for wideband EMF exposure assessment

LEXNET project, funded by the European Commission, is introducing new concepts for the assessment of the population EMF exposure. It also aims at evaluating the capability of future technologies to reduce this EMF exposure. The platform presented in this paper is an original tool for a continuous measurement of the multi-band downlink Electric Field strength at a scale of a city, relying on the SmartSantander sensor network that was developed in a previous project. The testbed integrates a new equipment to capture the E-field strength, i.e. connected dosimeters. The work that is reported here focuses on the deployment of those dosimeters in the city of Santander. The presented methodology uses both simulation and measurement to achieve an optimal design, i.e. a dosimeter deployment that provides relevant exposure statistics and allows for the creation of exposure maps. Results on the pre-deployment simulations are given in this document, while the complete design optimization will be demonstrated later in Year 2015

Odderon and Pomeron from the Vacuum Correlator Method

Glueball masses with J<=7 are computed both for C=+1 and C=-1 using the string Hamiltonian derived in the framework of the Vacuum Correlator Method. No fitting parameters are used, and masses are expressed in terms of string tension $\sigma$ and effective value of $\alpha_s$. We extend the calculations done for J<=3 using the same Hamiltonian, which provided glueball masses in good agreement with existing lattice data, to higher mass states. It is shown that 3^{--}, 5^{--} and 7^{--} states lie on the odderon trajectories with the intercept around or below 0.14. Another odderon trajectory with 3g glueballs of Y-shape, corresponds to 11% higher masses and low intercept. These findings are in agreement with recent experimental data, setting limits on the odderon contribution to the exclusive $\gamma p$ reactions.Comment: 16 pages. Journal version. To be published in Phys.Lett.

Hybrid mesons and auxiliary fields

Hybrid mesons are exotic mesons in which the color field is not in the ground state. Their understanding deserves interest from a theoretical point of view, because it is intimately related to nonperturbative aspects of QCD. Moreover, it seems that some recently detected particles, such as the $\pi_1(1600)$ and the Y(4260), are serious hybrid candidates. In this work, we investigate the description of such exotic hadrons by applying the auxiliary fields technique to the widely used spinless Salpeter Hamiltonian with appropriate linear confinement. Instead of the usual numerical resolution, this technique allows to find simplified analytical mass spectra and wave functions of the Hamiltonian, which still lead to reliable qualitative predictions. We analyse and compare two different descriptions of hybrid mesons, namely a two-body $q\bar q$ system with an excited flux tube, or a three-body $q\bar q g$ system. We also compute the masses of the $1^{-+}$ hybrids. Our results are shown to be in satisfactory agreement with lattice QCD and other effective models.Comment: 19 pages, 4 figure

The Physics of the B Factories

This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Optical Tweezers Approaches for Probing Multiscale Protein Mechanics and Assembly

Multi-step assembly of individual protein building blocks is key to the formation of essential higher-order structures inside and outside of cells. Optical tweezers is a technique well suited to investigate the mechanics and dynamics of these structures at a variety of size scales. In this mini-review, we highlight experiments that have used optical tweezers to investigate protein assembly and mechanics, with a focus on the extracellular matrix protein collagen. These examples demonstrate how optical tweezers can be used to study mechanics across length scales, ranging from the single-molecule level to fibrils to protein networks. We discuss challenges in experimental design and interpretation, opportunities for integration with other experimental modalities, and applications of optical tweezers to current questions in protein mechanics and assembly