286 research outputs found
XQCAT: eXtra Quark Combined Analysis Tool
XQCAT (eXtra Quark Combined Analysis Tool) is a tool aimed at determining
exclusion confidence levels for scenarios of new physics characterised by the
presence of one or multiple heavy extra quarks which interact through Yukawa
couplings with any of the Standard Model quarks. The code uses a database of
efficiencies for pre-simulated processes of QCD-induced pair production of
extra quarks and their subsequent on-shell decays. In the version 1.2 of XQCAT
the efficiencies have been computed for a set of seven publicly available
search results by the CMS experiment. The input for the code is a text file in
which masses, branching ratios and dominant chirality of the couplings of the
new quarks are provided. The output of the code is the exclusion confidence
levels of the test point for each implemented experimental analysis considered
individually and, when possible, in statistical combination.Comment: 18 pages, 2 figures, version accepted for publication in Comp. Phys.
Comm., fixed formatting problems caused by the arXiv's autotex syste
Framework for Model Independent Analyses of Multiple Extra Quark Scenarios
In this paper we present an analysis strategy and a dedicated tool to
determine the exclusion confidence level for any scenario involving multiple
heavy extra quarks with generic decay channels, as predicted in several
extensions of the Standard Model. We have created, validated and used a
software package, called XQCAT (eXtra Quark Combined Analysis Tool), which is
based on publicly available experimental data from direct searches for top
partners and from Supersymmetry inspired searches. By means of this code, we
recast the limits from CMS on new heavy extra quarks considering a complete set
of decay channels. The resulting exclusion confidence levels are presented for
some simple scenarios with multiple states and general coupling assumptions.
Highlighting the importance of combining multiple topology searches to obtain
accurate re-interpretations of the existing searches, we discuss the reach of
the SUSY analyses so as to set bounds on new quark resonances. In particular,
we report on the re-interpretation of the existing limits on benchmark
scenarios with one and multiple pair-produced top partners having non-exclusive
couplings to the third Standard Model generation of quarks.Comment: 31 pages, 6 figures, 3 tables, version accepted for publication in
JHE
Atomtronics with holes: Coherent transport of an empty site in a triple well potential
We investigate arrays of three traps with two fermionic or bosonic atoms. The
tunneling interaction between neighboring sites is used to prepare multi-site
dark states for the empty site, i.e., the hole, allowing for the coherent
manipulation of its external degrees of freedom. By means of an ab initio
integration of the Schr\"odinger equation, we investigate the adiabatic
transport of a hole between the two extreme traps of a triple-well potential.
Furthermore, a quantum-trajectory approach based on the de Broglie-Bohm
formulation of quantum mechanics is used to get physical insight into the
transport process. Finally, we discuss the use of the hole for the construction
of a coherent single hole diode and a coherent single hole transistor.Comment: 9 pages, 6 figure
XQCAT: eXtra Quark Combined Analysis Tool
XQCAT (eXtra Quark Combined Analysis Tool) is a tool aimed at determining exclusion confidence levels for scenarios of new physics characterised by the presence of one or multiple heavy extra quarks which interact through Yukawa couplings with any of the Standard Model quarks. The code uses a database of efficiencies for pre-simulated processes of QCD-induced pair production of extra quarks and their subsequent on-shell decays. In the version 1.2 of XQCAT the efficiencies have been computed for a set of seven publicly available search results by the CMS experiment. The input for the code is a text file in which masses, branching ratios and dominant chirality of the couplings of the new quarks are provided. The output of the code is the exclusion confidence levels of the test point for each implemented experimental analysis considered individually and, when possible, in statistical combination
Multiple micro-optical atom traps with a spherically aberrated laser beam
We report on the loading of atoms contained in a magneto-optic trap into
multiple optical traps formed within the focused beam of a CO_{2} laser. We
show that under certain circumstances it is possible to create a linear array
of dipole traps with well separated maxima. This is achieved by focusing the
laser beam through lenses uncorrected for spherical aberration. We demonstrate
that the separation between the micro-traps can be varied, a property which may
be useful in experiments which require the creation of entanglement between
atoms in different micro-traps. We suggest other experiments where an array of
these traps could be useful.Comment: 10 pages, 3 figure
Kinetic and morphological differentiation of Ettringites in plain and blended Portland cements using Metakaolin and the ASTM C 452-68 test. Part I: kinetic differentiation.
22 pages, 3 figures, 5 tables.[ES] En esta Parte I de la investigación, se han logrado verifi-
car mediante el ensayo ASTM C 452-68, los resultados
obtenidos en anteriores investigaciones realizadas con
DRX y SEM y el ensayo Le Chatelier-Ansttet. Para ello, a
10 cementos Portland –6 CPO y 4 CPRS– se les añadió
20%, 30% y 40% de metakaolÃn (MK). Tanto los 10 CP
como los 30 de sus mezclas con metakaolÃn (MK), se
ensayaron durante 2 años, mediante dicho método ASTM
C 452-68, y a sus probetas no sólo se les determinó su
incremento porcentual de longitud, ∆L(%), sino además,
el contenido de sulfatos de sus aguas de conservación.
Otras determinaciones complementarias fueron: análisis
quÃmico de los materiales cementiceos utilizados y pro-
piedades especÃficas de algunos cementos ensayados.
Los resultados experimentales, ∆L(%) frente al tiempo,
han confirmado de nuevo que la velocidad de formación
de la ettringita de origen alúmina reactiva, Al2O3 r-, de las
puzolanas, tiene que ser considerablemente mayor que la
velocidad de formación de la ettringita de origen C3A de
los CP, lo que ha sido verificado por la evolución durante
todo el ensayo, del contenido de sulfatos de las aguas de
conservación de las probetas. Debido a ello, se ha pro-
puesto denominar a ambos tipos de ettringitas, ettringita
de rápida formación, ett-rf, y ettringita de lenta forma-
ción, ett-lf, respectivamente.[EN] In this first part of the study, the results obtained in prior
research with XRD and SEM, as well as the Le Chatelier-
Ansttet test were confirmed with the ASTM C 452-68 test.
To this end, 20%, 30% and 40% metakaolin (MK) was
added to ten Portland cements, six OPCs and four SRPCs.
Both the ten plain PCs and the 30 metakaolin (MK) blends
were tested for two years under ASTM C 452-68 specifications,
determining not only the percentage increase in
length, ΔL(%), of the specimens, but also the sulphate
content in the curing water. Other parameters studied
included: chemical analysis of the cementitious materials
used and specific properties of some of the cements tested.
The experimental results, ΔL(%) versus time, re-confirmed
that the formation rate of ettringite from the reactive
alumina, Al2O3
r-, present in the pozzolan must be substantially
higher than the formation rate of ettringite from
the C3A present in the PC. This was verified by the variation
of the sulphate content in the specimen curing water
throughout the test. In light of those findings, in this article
these two types of ettringite are denominated rapid
forming ettringite or ett-rf, and slow forming ettringite
or ett-lf.Peer reviewe
Coherent manipulation of atomic qubits in optical micropotentials
We experimentally demonstrate the coherent manipulation of atomic states in
far-detuned dipole traps and registers of dipole traps based on two-dimensional
arrays of microlenses. By applying Rabi, Ramsey, and spin-echo techniques, we
systematically investigate the dephasing mechanisms and determine the coherence
time. Simultaneous Ramsey measurements in up to 16 dipole traps are performed
and proves the scalability of our approach. This represents an important step
in the application of scalable registers of atomic qubits for quantum
information processing. In addition, this system can serve as the basis for
novel atomic clocks making use of the parallel operation of a large number of
individual clocks each remaining separately addressable.Comment: to be published in Appl. Phys.
Implications of SU(2) symmetry on the dynamics of population difference in the two-component atomic vapor
We present an exact many body solution for the dynamics of the population
difference induced by an rf-field in the two-component atomic cloud
characterized by equal scattering lengths. This situation is very close to the
actual JILA experiments with the two-component Rb vapor. We show that no
intrinsic decoherence exists for , provided the exact SU(2) symmetry
holds. This contrasts with finite dissipation of the normal modes even in the
presence of the SU(2) symmetry. The intrinsic decoherence for \ may
occur as long as deviations from the exact SU(2) symmetry are taken into
account. Such decoherence, however, should be characterized by very long times
governed by the smallness of the deviations from the symmetry. We suggest
testing the evolution of by conducting echo-type experiments.Comment: 5 RevTex pages, no figures, typos correcte
Wave Packet Echoes in the Motion of Trapped Atoms
We experimentally demonstrate and systematically study the stimulated revival
(echo) of motional wave packet oscillations. For this purpose, we prepare wave
packets in an optical lattice by non-adiabatically shifting the potential and
stimulate their reoccurence by a second shift after a variable time delay. This
technique, analogous to spin echoes, enables one even in the presence of strong
dephasing to determine the coherence time of the wave packets. We find that for
strongly bound atoms it is comparable to the cooling time and much longer than
the inverse of the photon scattering rate
Implications of a High-Mass Diphoton Resonance for Heavy Quark Searches
Heavy vector-like quarks coupled to a scalar will induce a coupling of
this scalar to gluons and possibly (if electrically charged) photons. The decay
of the heavy quark into , with being a Standard Model quark, provides,
if kinematically allowed, new channels for heavy quark searches. Inspired by
naturalness considerations, we consider the case of a vector-like partner of
the top quark. For illustration, we show that a singlet partner can be searched
for at the 13TeV LHC through its decay into a scalar resonance in the
final states, especially if the diphoton branching ratio of
the scalar is further enhanced by the contribution of non coloured
particles. We then show that conventional heavy quark searches are also
sensitive to this new decay mode, when decays hadronically, by slightly
tightening the current selection cuts. Finally, we comment about the
possibility of disentangling, by scrutinising appropriate kinematic
distributions, heavy quark decays to from other standard decay modes.Comment: 8 pages, 3 figures and 1 table; v3: typos fixed. Matches published
versio
- …