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Author |
Binosi, D.; Papavassiliou, J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Gauge invariant Ansatz for a special three-gluon vertex |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
121 - 23pp |
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Keywords |
Nonperturbative Effects; QCD |
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Abstract |
We construct a general Ansatz for the three-particle vertex describing the interaction of one background and two quantum gluons, by simultaneously solving the Ward and Slavnov-Taylor identities it satisfies. This vertex is known to be essential for the gauge-invariant truncation of the Schwinger-Dyson equations of QCD, based on the pinch technique and the background field method. A key step in this construction is the formal derivation of a set of crucial constraints (shown to be valid to all orders), relating the various form factors of the ghost Green's functions appearing in the aforementioned Slavnov-Taylor identity. When inserted into the Schwinger-Dyson equation for the gluon propagator, this vertex gives rise to a number of highly non-trivial cancellations, which are absolutely indispensable for the self-consistency of the entire approach. |
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Address |
[Binosi, D.] European Ctr Theoret Studies Nucl Phys & Related, I-38123 Villazzano, TN, Italy, Email: binosi@ect.it |
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Springer |
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English |
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ISSN |
1126-6708 |
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ISI:000289295300049 |
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no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
624 |
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Permanent link to this record |
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Author |
Aguilar, A.C.; Binosi, D.; Papavassiliou, J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Gluon mass through ghost synergy |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
01 |
Issue |
1 |
Pages |
050 - 32pp |
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Keywords |
Nonperturbative Effects; QCD |
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Abstract |
In this work we compute, at the “one-loop-dressed” level, the nonperturbative contribution of the ghost loops to the self-energy of the gluon propagator, in the Landau gauge. This is accomplished within the PT-BFM formalism, where the contribution of the ghost-loops is inherently transverse, by virtue of the QED-like Ward identities satisfied in this framework. At the level of the “one-loop dressed” approximation, the ghost transversality is preserved by employing a suitable gauge-technique Ansatz for the longitudinal part of the full ghost-gluon vertex. Under the key assumption that the undetermined transverse part of this vertex is numerically subleading in the infrared, and using as nonperturbative input the available lattice data for the ghost dressing function, we show that the ghost contributions have a rather sizable effect on the overall shape of the gluon propagator, both for d = 3, 4. Then, by exploiting a recently introduced dynamical equation for the effective gluon mass, whose solutions depend crucially on the characteristics of the gluon propagator at intermediate energies, we show that if the ghost loops are removed from the gluon propagator then the gluon mass vanishes. These findings suggest that, at least at the level of the Schwinger-Dyson equations, the effects of gluons and ghosts are inextricably connected, and must be combined suitably in order to reproduce the results obtained in the recent lattice simulations. |
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Address |
[Aguilar, A. C.] Fed Univ ABC, CCNH, BR-09210170 Santo Andre, Brazil, Email: arlene.aguilar@ufabc.edu.br |
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Springer |
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English |
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1126-6708 |
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Notes |
WOS:000300181800050 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
969 |
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Author |
Beneke, M.; Hellmann, C.; Ruiz-Femenia, P. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Non-relativistic pair annihilation of nearly mass degenerate neutralinos and charginos I. General framework and S-wave annihilation |
Type |
Journal Article |
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Year |
2013 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
148 - 48pp |
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Keywords |
Cosmology of Theories beyond the SM; Supersymmetric Standard Model; Nonperturbative Effects |
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Abstract |
We compute analytically the tree-level annihilation rates of a collection of non-relativistic neutralino and chargino two-particle states in the general MSSM, including the previously unknown off-diagonal rates. The results are prerequisites to the calculation of the Sommerfeld enhancement in the MSSM, which will be presented in subsequent work. They can also be used to obtain concise analytic expressions for MSSM dark matter pair annihilation in the present Universe for a large number of exclusive two-particle final states. |
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Address |
Tech Univ Munich, Phys Dept T31, D-85748 Garching, Germany, Email: mbeneke@physik.rwth-aachen.de; |
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Springer |
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English |
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1029-8479 |
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Notes |
WOS:000317522400060 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
1437 |
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Permanent link to this record |
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Author |
Hellmann, C.; Ruiz-Femenia, P. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Non-relativistic pair annihilation of nearly mass degenerate neutralinos and charginos II. P-wave and next-to-next-to-leading order S-wave coefficients |
Type |
Journal Article |
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Year |
2013 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
08 |
Issue |
8 |
Pages |
084 - 49pp |
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Keywords |
Cosmology of Theories beyond the SM; Supersymmetric Standard Model; Nonperturbative Effects |
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Abstract |
This paper is a continuation of an earlier work (arXiv:1210.7928) which computed analytically the tree-level annihilation rates of a collection of non-relativistic neutralino and chargino two-particle states in the general MSSM. Here we extend the results by providing the next-to-next-to-leading order corrections to the rates in the non-relativistic expansion in momenta and mass differences, which include leading P-wave effects, in analytic form. The results are a necessary input for the calculation of the Sommerfeld-enhanced dark matter annihilation rates including short-distance corrections at next-to-next-to-leading order in the non-relativistic expansion in the general MSSM with neutralino LSP. |
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Address |
[Hellmann, C.] Tech Univ Munich, Phys Dept T31, D-85748 Garching, Germany, Email: charlotte.hellmann@tum.de; |
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Publisher |
Springer |
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English |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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ISSN |
1029-8479 |
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Expedition |
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Conference |
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Notes |
WOS:000324113700084 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
1594 |
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Permanent link to this record |
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Author |
Binosi, D.; Ibañez, D.; Papavassiliou, J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Nonperturbative study of the four gluon vertex |
Type |
Journal Article |
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Year |
2014 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
09 |
Issue |
9 |
Pages |
059 - 32pp |
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Keywords |
Nonperturbative Effects; QCD; Confinement |
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Abstract |
In this paper we study the nonperturbative structure of the SU(3) four-gluon vertex in the Landau gauge, concentrating on contributions quadratic in the metric. We employ an approximation scheme where “one-loop” diagrams are computed using fully dressed gluon and ghost propagators, and tree-level vertices. When a suitable kinematical configuration depending on a single momentum scale p is chosen, only two structures emerge: the tree-level four-gluon vertex, and a tensor orthogonal to it. A detailed numerical analysis reveals that the form factor associated with this latter tensor displays a change of sign (zero-crossing) in the deep infrared, and finally diverges logarithmically. The origin of this characteristic behavior is proven to be entirely due to the masslessness of the ghost propagators forming the corresponding ghost-loop diagram, in close analogy to a similar effect established for the three-gluon vertex. However, in the case at hand, and under the approximations employed, this particular divergence does not affect the form factor proportional to the tree-level tensor, which remains finite in the entire range of momenta, and deviates moderately from its naive tree-level value. It turns out that the kinematic configuration chosen is ideal for carrying out lattice simulations, because it eliminates from the connected Green's function all one-particle reducible contributions, projecting out the genuine one-particle irreducible vertex. Motivated by this possibility, we discuss in detail how a hypothetical lattice measurement of this quantity would compare to the results presented here, and the potential interference from an additional tensorial structure, allowed by Bose symmetry, but not encountered within our scheme. |
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Address |
[Binosi, D.; Ibanez, D.] European Ctr Theoret Studies Nucl Phys & Related, I-38123 Villazzano, TN, Italy, Email: binosi@ectstar.eu; |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1029-8479 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000342215400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
1954 |
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Permanent link to this record |