203 research outputs found
High Spin Glueballs from the Lattice
We discuss the principles underlying higher spin glueball calculations on the
lattice. For that purpose, we develop numerical techniques to rotate Wilson
loops by arbitrary angles in lattice gauge theories close to the continuum. As
a first application, we compute the glueball spectrum of the SU(2) gauge theory
in 2+1 dimensions for both parities and for spins ranging from 0 up to 4
inclusive. We measure glueball angular wave functions directly, decomposing
them in Fourier modes and extrapolating the Fourier coefficients to the
continuum. This allows a reliable labelling of the continuum states and gives
insight into the way rotation symmetry is recovered. As one of our results, we
demonstrate that the D=2+1 SU(2) glueball conventionally labelled as J^P = 0^-
is in fact 4^- and that the lightest ``J=1'' state has, in fact, spin 3.Comment: Minor changes in the text; the spin 4 glueball mass is taken further
out in Euclidean time at higher beta values. 41 pages, 20 figure
Current Profiles of Molecular Nanowires; DFT Green Function Representation
The Liouville-space Green function formalism is used to compute the current
density profile across a single molecule attached to electrodes. Time ordering
is maintained in real, physical, time, avoiding the use of artificial time
loops and backward propagations. Closed expressions for molecular currents,
which only require DFT calculations for the isolated molecule, are derived to
fourth order in the molecule/electrode coupling.Comment: 21 page
Properties of the Fixed Point Lattice Dirac Operator in the Schwinger Model
We present a numerical study of the properties of the Fixed Point lattice
Dirac operator in the Schwinger model. We verify the theoretical bounds on the
spectrum, the existence of exact zero modes with definite chirality, and the
Index Theorem. We show by explicit computation that it is possible to find an
accurate approximation to the Fixed Point Dirac operator containing only very
local couplings.Comment: 38 pages, LaTeX, 3 figures, uses style [epsfig], a few comments and
relevant references adde
Extracting Br(omega->pi^+ pi^-) from the Time-like Pion Form-factor
We extract the G-parity-violating branching ratio Br(omega->pi^+ pi^-) from
the effective rho-omega mixing matrix element Pi_{rho omega}(s), determined
from e^+e^- -> pi^+ pi^- data. The omega->pi^+ pi^- partial width can be
determined either from the time-like pion form factor or through the constraint
that the mixed physical propagator D_{rho omega}^{mu nu}(s) possesses no poles.
The two procedures are inequivalent in practice, and we show why the first is
preferred, to find finally Br(omega->pi^+ pi^-) = 1.9 +/- 0.3%.Comment: 12 pages (published version
Polaron Effective Mass, Band Distortion, and Self-Trapping in the Holstein Molecular Crystal Model
We present polaron effective masses and selected polaron band structures of
the Holstein molecular crystal model in 1-D as computed by the Global-Local
variational method over a wide range of parameters. These results are augmented
and supported by leading orders of both weak- and strong-coupling perturbation
theory. The description of the polaron effective mass and polaron band
distortion that emerges from this work is comprehensive, spanning weak,
intermediate, and strong electron-phonon coupling, and non-adiabatic, weakly
adiabatic, and strongly adiabatic regimes. Using the effective mass as the
primary criterion, the self-trapping transition is precisely defined and
located. Using related band-shape criteria at the Brillouin zone edge, the
onset of band narrowing is also precisely defined and located. These two lines
divide the polaron parameter space into three regimes of distinct polaron
structure, essentially constituting a polaron phase diagram. Though the
self-trapping transition is thusly shown to be a broad and smooth phenomenon at
finite parameter values, consistency with notion of self-trapping as a critical
phenomenon in the adiabatic limit is demonstrated. Generalizations to higher
dimensions are considered, and resolutions of apparent conflicts with
well-known expectations of adiabatic theory are suggested.Comment: 28 pages, 15 figure
Partial Wave Analysis of
BES data on are presented. The
contribution peaks strongly near threshold. It is fitted with a
broad resonance with mass MeV, width MeV. A broad resonance peaking at 2020 MeV is also required
with width MeV. There is further evidence for a component
peaking at 2.55 GeV. The non- contribution is close to phase
space; it peaks at 2.6 GeV and is very different from .Comment: 15 pages, 6 figures, 1 table, Submitted to PL
Placing Joseph Banks in the North Pacific
The South Pacific was a fulcrum of Joseph Banks's maritime world and global networks. The North Pacific was a distance and intangible fringe. This article is concerned with how Banks should be ‘placed’ in the North Pacific. It tracks how Banks's activities have been delineated in terms of languages and categories of global and local, and centre and margin, and then considers the historical and geographical specifics apposite to his connection to the North Pacific. In this setting, ideas of place (as location and assignment) and capital (as a circulatory and everyday practice of exchange and opportunism) come into view and question the distinction between science and commerce in Banks historiography. The article considers a diverse group of non-Indigenous figures – explorers, traders, cartographers, scientists, collectors – operating in the North Pacific in the 1780s and 1790s whose initiatives and missives passed across Banks's desk, and assesses their place in Banks's archive by drawing on Peter Sloterdijk's ideas about the interiorising and exteriorising logic of capital.PostprintPeer reviewe
Mapping of quantitative trait loci for thermosensitive genic male sterility in indica rice
Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV
Peer reviewe
Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector
This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 < kappa(lambda) < 12.0 (-5.8 < kappa(lambda) < 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p
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