1,500 research outputs found
Ratios of Fluctuation Observables in the Search for the QCD Critical Point
The QCD critical point can be found in heavy ion collision experiments via
the non-monotonic behavior of many fluctuation observables as a function of the
collision energy. The event-by-event fluctuations of various particle
multiplicities are enhanced in those collisions that freeze out near the
critical point. Higher, non-Gaussian, moments of the event-by-event
distributions of such observables are particularly sensitive to critical
fluctuations, since their magnitude depends on the critical correlation length
to a high power. We present quantitative estimates of the contribution of
critical fluctuations to the third and fourth moments of the pion and proton,
as well as estimates of various measures of pion-proton correlations, all as a
function of the same five non-universal parameters. We show how to use
nontrivial but parameter independent ratios among these more than a dozen
fluctuation observables to discover the critical point. We also construct
ratios that, if the critical point is found, can be used to overconstrain the
values of the non-universal parameters.Comment: 5 pages, 1 figure - Talk given by C. Athanasiou at Hot Quarks 201
Radiation of a circulating quark in strongly coupled N=4 super Yang-Mills theory
The energy density and angular distribution of power radiated by a quark
undergoing circular motion in strongly coupled supersymmetric
Yang-Mills (SYM) theory is computed using gauge/gravity duality. The results
are qualitatively similar to that of synchrotron radiation produced by an
electron in circular motion in classical electrodynamics: At large velocities
the quark emits radiation in a narrow beam along its velocity vector with a
characteristic opening angle and radial thickness
scaling like .Comment: 8 pages, 2 figures - Talk presented by D. Nickel at QCD@Work, June
20-23rd, 2010, Martina Franca, Ital
Synchrotron radiation in strongly coupled conformal field theories
Using gauge/gravity duality, we compute the energy density and angular
distribution of the power radiated by a quark undergoing circular motion in
strongly coupled supersymmetric Yang-Mills (SYM) theory. We
compare the strong coupling results to those at weak coupling, and find the
same angular distribution of radiated power, up to an overall prefactor. In
both regimes, the angular distribution is in fact similar to that of
synchrotron radiation produced by an electron in circular motion in classical
electrodynamics: the quark emits radiation in a narrow beam along its velocity
vector with a characteristic opening angle . To an
observer far away from the quark, the emitted radiation appears as a short
periodic burst, just like the light from a lighthouse does to a ship at sea.
Our strong coupling results are valid for any strongly coupled conformal field
theory with a dual classical gravity description.Comment: 20 pages, 8 figures. v2: published version. v4: factor-of-two error
corrected in the time-averaged angular distribution of the power radiated in
scalars in weak coupling N=4 SYM theory; correcting this error has
interesting ramification
Probing Supersymmetry With Third-Generation Cascade Decays
The chiral structure of supersymmetric particle couplings involving third
generation Standard Model fermions depends on left-right squark and slepton
mixings as well as gaugino-higgsino mixings. The shapes and intercorrelations
of invariant mass distributions of a first or second generation lepton with
bottoms and taus arising from adjacent branches of SUSY cascade decays are
shown to be a sensitive probe of this chiral structure. All possible cascade
decays that can give rise to such correlations within the MSSM are considered.
For bottom-lepton correlations the distinctive structure of the invariant mass
distributions distinguishes between decays originating from stop or sbottom
squarks through either an intermediate chargino or neutralino. For decay
through a chargino the spins of the stop and chargino are established by the
form of the distribution. When the bottom charge is signed through soft muon
tagging, the structure of the same-sign and opposite-sign invariant mass
distributions depends on a set function of left-right and gaugino-higgsino
mixings, as well as establishes the spins of all the superpartners in the
sequential two-body cascade decay. Tau-lepton and tau-tau invariant mass
distributions arising from MSSM cascade decays are likewise systematically
considered with particular attention to their dependence on tau polarization.
All possible tau-lepton and tau-tau distributions are plotted using a
semi-analytic model for hadronic one-prong taus. Algorithms for fitting tau-tau
and tau-lepton distributions to data are suggested.Comment: 35 pages, 17 .eps figure
An Anxiety Epidemic in the Financialized University: Critical questions and Unexpected Resistance
Financialization is transforming social subjects and institutions, including the university. This article explores overlooked links between the financialization of public postsecondary education on both sides of the North Atlantic and the ongoing “anxiety epidemic” among students (and, indeed, staff). The article argues that the “anxious university” represents a unique space to study the economic, political, social, and cultural impact of the rise in power and influence of the financial sector. By unraveling the complex sociological dimensions of the anxiety epidemic, we offer a vantage on the emergence of new forms an
Strongly-Coupled Quarks and Colorful Black Holes
We use the AdS/CFT correspondence to study the behavior of strongly-coupled
quarks in a black hole background. The supergravity background consists of a
six-dimensional Schwarzschild-black string AdS soliton, for which the bulk
horizon extends from the AdS boundary down to an infra-red floor. By going to
higher energy scales, the regime of validity of the classical supergravity
background can be extended closer to the singularity than might be expected
from the four-dimensional perspective. Small black holes potentially created by
the Large Hadron Collider could typically carry color charges inherited from
their parton progenitors. The dynamics of quarks near such a black hole depends
on the curved spacetime geometry as well as the strong interaction with the
color-charged black hole. We study the resulting behavior of quarks and compute
the rate at which a quark rotating around the black hole loses energy. We also
investigate how the interaction between a quark and an antiquark is altered by
the presence of the black hole, which results in a screening length.Comment: Proceedings of the DPF-2011 Conference, 8 pages, 5 figures, added
reference
The laboratory diagnostic approach to thoracic and abdominal effusions in the dog, cat, and horse
Περιστατικά στα οποία διαπιστώνονται υπεζωκοτικές και περιτοναϊκές συλλογές είναι αρκετά συχνά στην κλινική πράξη. Ο καθορισμός της υποκείμενης αιτιολογίας σε αυτές τις περιπτώσεις βασίζεται κυρίως στην ανάλυση του υγρού της συλλογής. Η τεχνική που χρησιμοποιείται για τη λήψη του υγρού της υπεζωκοτικής ή περιτοναϊκής συλλογής μπορεί να επηρεάσει σε μεγάλο βαθμό τα αποτελέσματα της ανάλυσης. Στις πιο συχνά χρησιμοποιούμενες διαγνωστικές εξετάσεις περιλαμβάνονται η αξιολόγηση των φυσικών ιδιοτήτων του υγρού, ο προσδιορισμός του συνολικού αριθμού εμπύρηνων κυττάρων / ολικών πρωτεϊνών (TNCC / TP), ο προσδιορισμός χημικών / βιοχημικών παραμέτρων (γαλακτική αφυδρογονάση και γαλακτικό οξύ, χολοστερόλη, τριγλυκερίδια, γλυκόζη, κρεατινίνη, pH, pO2, pCO2, K), κυτταρολογική εξέταση (διάγνωση σηπτικών και μη σηπτικών φλεγμονών και νεοπλασμάτων), μικροβιολογικές εξετάσεις (επιχρίσματα με χρώση Gram, καλλιέργεια, μοριακές τεχνικές) και ειδικές διαγνωστικές εξετάσεις για ορισμένες παθολογικές καταστάσεις και νοσήματα. Η ταξινόμηση μιας συλλογής ως διίδρωμα, τροποποιημένο διίδρωμα και εξίδρωμα βασίζεται παραδοσιακά στις τιμές των TNCC και ΤΡ. Νέες διαγνωστικές μέθοδοι συνεισφέρουν στην αιτιολογική διάγνωση χωρίς απαραίτητα να ακολουθηθεί αυστηρά η παραδοσιακή ταξινόμηση. Πολλές από τις διαγνωστικές εξετάσεις που περιγράφονται σε αυτήν την ανασκόπηση είναι απλές και μπορούν να πραγματοποιηθούν στο ιατρείο, παρέχοντας γρήγορα πληροφορίες στον κλινικό κτηνίατρο σχετικές με την αιτία της συλλογής. Η γνώση αυτή είναι απαραίτητη για την έγκαιρη και αποτελεσματική θεραπευτική αντιμετώπιση της υποκείμενης παθολογικής κατάστασης.Cases involving pleural and peritoneal effusions occur relatively frequently in clinical practice. Determining the underlying etiology in these cases relies mainly on fluid analysis. The technique used for obtaining the pleural or peritoneal fluid can impact greatly the results of the analysis. Most often used diagnostic tools include evaluation of gross appearance, Total Nucleated Cell Count / Total Protein (TNCC/TP) measurement, chemical/biochemical analysis (Lactate dehydrogenase and lactate, cholesterol, triglycerides, glucose, creatinine, pH, pO2, pCO2, and K measurements), cytology (identification of septic and non-septic inflammation and neoplasia), microbiology (Gram stain, culture, molecular techniques), and specific tests for certain clinical conditions and diseases. Classifying an effusion as transudate, modified transudate and exudate is traditionally based on the TNCC and TP values. New diagnostic methods encourage the clinician to approach the effusion etiologically instead of strictly following this traditional classification. Many of the diagnostic tests described in this review are simple and can be performed in-house, providing the clinician quickly with information about the cause of the effusion, essential for an effective treatment plan without wasting valuable time
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