4,940 research outputs found
BFT embedding of the Green-Schwarz superstring and the pure spinor formalism
We worked out the Batalin-Fradkin-Tyutin (BFT) conversion program of second
class constraints to first class constraints in the GS superstring using light
cone coordinates. By applying this systematic procedure we were able to obtain
a gauge system that is equivalent to the recent model proposed by Berkovits and
Marchioro to relate the GS superstring to the pure spinor formalism.Comment: 12 pages latex2e, v2 typos fixed, v3 published in JHE
Incident-energy dependence of the effective temperature in heavy-ion collisions
We study the behaviour of the effective temperature for K+ in several energy domains. For this purpose, we apply the recently developed SPheRIO code for hydrodynamics in 3+1 dimensions, using both Landau-type compact initial conditions and spatially more spread ones. We show that initial conditions given in small volume, like Landau-type ones, are unable to reproduce the effective temperature together with other data (multiplicities and rapidity distributions). These quantities can be reproduced altogether only when using a large initial volume with an appropriate velocity distribution
Towards Pure Spinor Type Covariant Description of Supermembrane -- An Approach from the Double Spinor Formalism --
In a previous work, we have constructed a reparametrization invariant
worldsheet action from which one can derive the super-Poincare covariant pure
spinor formalism for the superstring at the fully quantum level. The main idea
was the doubling of the spinor degrees of freedom in the Green-Schwarz
formulation together with the introduction of a new compensating local
fermionic symmetry. In this paper, we extend this "double spinor" formalism to
the case of the supermembrane in 11 dimensions at the classical level. The
basic scheme works in parallel with the string case and we are able to
construct the closed algebra of first class constraints which governs the
entire dynamics of the system. A notable difference from the string case is
that this algebra is first order reducible and the associated BRST operator
must be constructed accordingly. The remaining problems which need to be solved
for the quantization will also be discussed.Comment: 40 pages, no figure, uses wick.sty; v2: a reference added, published
versio
Pure-spinor superstrings in d=2,4,6
We continue the study of the d=2,4,6 pure-spinor superstring models
introduced in [1]. By explicitly solving the pure-spinor constraint we show
that these theories have vanishing central charge and work out the (covariant)
current algebra for the Lorentz currents. We argue that these super-Poincare
covariant models may be thought of as compactifications of the superstring on
CY_{4,3,2}, and take some steps toward making this precise by constructing a
map to the RNS superstring variables. We also discuss the relation to the so
called hybrid superstrings, which describe the same type of compactifications.Comment: 27 page
Origin of Pure Spinor Superstring
The pure spinor formalism for the superstring, initiated by N. Berkovits, is
derived at the fully quantum level starting from a fundamental
reparametrization invariant and super-Poincare invariant worldsheet action. It
is a simple extension of the Green-Schwarz action with doubled spinor degrees
of freedom with a compensating local supersymmetry on top of the conventional
kappa-symmetry. Equivalence to the Green-Schwarz formalism is manifest from the
outset. The use of free fields in the pure spinor formalism is justified from
the first principle. The basic idea works also for the superparticle in 11
dimensions.Comment: 21 pages, no figure; v2: refs. adde
On Fermionic T-duality of Sigma modes on AdS backgrounds
We study the fermionic T-duality symmetry of integrable Green-Schwarz sigma
models on AdS backgrounds. We show that the sigma model on
background is self-dual under fermionic T-duality. We also construct new
integrable sigma models on . These backgrounds could be
realized as supercosets of SU supergroups for arbitrary , but could also be
realized as supercosets of OSp supergroups for . We find that the
supercosets based on SU supergroups are self-dual under fermionic T-duality,
while the supercosets based on OSp supergroups are not. However, the reasons of
OSp supercosets being not self-dual under fermionic T-duality are different.
For case, corresponding to background, the
failure is due to the singular fermionic quadratic terms, just like
case. For case, the failure is due to the
shortage of right number of -symmetry to gauge away the fermionic
degrees of freedom, even though the fermionic quadratic term is not singular
any more. More general, for the supercosets of the OSp supergroups with
superalgebra , including and
backgrounds, the sigma models are not self-dual under fermionic T-duality as
well, obstructed by the -symmetry.Comment: 17 pages; Clarfications on kappa symmetries, references
added;Published versio
Note About Classical Dynamics of Pure Spinor String on AdS_5 x S_5 Background
We will discuss some properties of the pure spinor string on the AdS_5 x S_5
background. Using the classical Hamiltonian analysis we will show that the
vertex operator for the massless state that is in the cohomology of the BRST
charges describes on-shell fluctuations around AdS_5 x S_5 background.Comment: 26. pages, added references, v2:corrected typo
Immunogenomics of Colorectal Tumors: Facts and Hypotheses on an Evolving Saga
Different mutational burden only partially explains the different response of MSI and MSS CRCs to immunotherapy.
Neoantigen load, as measured using available prediction algorithms, is not sufficiently accurate for implementation into clinical decision making.
Abundant immune infiltration in the tumor tissue is likely to have high prognostic value, but not an equally high predictive value in terms of response to immunotherapy.
The intrinsic characteristics of MSI and MSS CRCs determine differences in their evolutionary paths, which inevitably influence the way the immune system sculpts tumor clonal and subclonal dynamics.
Immunotherapy with immune checkpoint inhibitors is an approved treatment option for a subpopulation of patients with colorectal cancers that display microsatellite instability. However, not all individuals within this subgroup respond to immunotherapy, and molecular biomarkers for effective patient stratification are still lacking. In this opinion article, we provide an overview of the different biological parameters that contribute to rendering colorectal cancers with microsatellite instability potentially sensitive to immunotherapy. We critically discuss the reasons why such parameters have limited predictive value and the implications therein. We also consider that a more informed knowledge of response determinants in this tumor subtype could help understand the mechanisms of immunotherapy resistance in microsatellite stable tumors. We conclude that the dynamic nature of the interactions between cancer and immune cells complicates conventional biomarker development and argue that a new generation of adaptive metrics, borrowed from evolutionary genetics, may improve the effectiveness and reliability of clinical decision making
Spectral Degeneracy in Supersymmetric Gluodynamics and One-Flavor QCD related to N=1/2 SUSY
In supersymmetric gluodynamics (N=1 super-Yang-Mills theory) we show that the
spectral functions induced by the nonchiral operator Tr G_{\alpha\beta}
\bar\lambda^2 are fully degenerate in the J^{PC}=1^{\pm -} channels. The above
operator is related to N=1/2 generalization of SUSY. Using the planar
equivalence, this translates into the statement of degeneracy between the
mesons produced from the vacuum by the operators (\bar \Psi \vec E\Psi + i\bar
\Psi \vec B \gamma^5\Psi) and (\bar \Psi \vec B\Psi - i\bar \Psi \vec E
\gamma^5\Psi) in one-flavor QCD, up to 1/N corrections. Here \Psi is the quark
field, and \vec E ,\vec B are chromoelectric/chromomagnetic fields,
respectively.Comment: Latex, 6 pages, two references adde
- …