Complete tree level calculation of the process and the Higgs signal at LEP200 and next linear colliders

1994 ◽  
Vol 329 (2-3) ◽  
pp. 379-385 ◽  
Author(s):  
M. Dubinin ◽  
V. Edneral ◽  
Y. Kurihara ◽  
Y. Shimizu
Keyword(s):  
Tree Level ◽  
Linear Colliders ◽  
Complete Tree ◽  
Level Calculation ◽  
Higgs Signal

scholarly journals THE SUYAMA–YAMAGUCHI CONSISTENCY RELATION IN THE PRESENCE OF VECTOR FIELDS

2013 ◽  
Vol 28 (06) ◽  
pp. 1350012 ◽  
Author(s):  
JUAN P. BELTRÁN ALMEIDA ◽  
YEINZON RODRÍGUEZ ◽  
CÉSAR A. VALENZUELA-TOLEDO
Keyword(s):  
Distribution Function ◽  
Probability Distribution Function ◽  
Vector Fields ◽  
Tree Level ◽  
Microwave Background ◽  
Curvature Perturbation ◽  
Consistency Relation ◽  
Complete Tree ◽  
Level Calculation ◽  
Inflationary Models

We consider inflationary models in which vector fields (VF) are responsible for part or eventually all of the primordial curvature perturbation ζ. Such models are phenomenologically interesting since they naturally introduce anisotropies in the probability distribution function of the primordial fluctuations that can leave a measurable imprint in the cosmic microwave background. Assuming that non-Gaussianity (NG) is generated due to the superhorizon evolution, we use the δN formalism to do a complete tree level calculation of the NG parameters f NL and τ NL in the presence of VF. We isolate the isotropic pieces of the NG parameters, which anyway have contributions from the VF, and show that they obey the Suyama–Yamaguchi (SY) consistency relation [Formula: see text]. Other ways of defining the NG parameters, which could be observationally relevant, are stated and the respective SY-like consistency relations are obtained.

Full tree-level calculation of theqq→qqWZelectroweak process at hadron supercolliders

1992 ◽  
Vol 46 (5) ◽  
pp. 2028-2039 ◽  
Author(s):  
V. Barger ◽  
Kingman Cheung ◽  
T. Han ◽  
A. Stange ◽  
D. Zeppenfeld
Keyword(s):  
Tree Level ◽  
Level Calculation

scholarly journals The complete tree-level result up to order 1/Q for polarized deep-inelastic leptoproduction

1997 ◽  
Vol 484 (1-2) ◽  
pp. 538-540 ◽  
Author(s):  
P.J. Mulders ◽  
R.D. Tangerman
Keyword(s):  
Tree Level ◽  
Complete Tree

THE REACTION $e^+ e^- \to \nu\bar{\nu}b \bar{b}$ AND THE HIGGS SIGNAL AT LEP200 AND NLC

1995 ◽  
Vol 10 (14) ◽  
pp. 2067-2085 ◽  
Author(s):  
E. BOOS ◽  
M. SACHWITZ ◽  
H.J. SCHREIBER ◽  
S. SHICHANIN
Keyword(s):  
Cross Sections ◽  
Linear Collider ◽  
Computer Time ◽  
Standard Theory ◽  
Tree Level ◽  
Final State ◽  
The Matrix ◽  
Phase Space Integration ◽  
Three Body ◽  
Higgs Signal

A complete tree-level calculation of the reaction [Formula: see text] in the electroweak standard theory for the energy range of LEP200 and the Next Linear Collider is presented. The matrix elements were calculated by means of the package CompHEP, and phase space integration and event generation were carried out with the computer programs BASES/SPRING. Cross sections for the [Formula: see text] final state, the rate for Higgs production and for different background contributions are studied as a function of the cms energy and the Higgs mass in the range from 80 to 140 GeV. At LEP200 energies, the Higgs bremsstrahlung reaction and the two-body process e+e−→ZZ are dominant while near 500 GeV the Higgs fusion and two-to-three body background processes govern the [Formula: see text] final state. Interference patterns were searched for and found to be negligible except for [Formula: see text], where interferences are found to be of comparable strength with the Higgs signal diagrams. Some cancellations between different background diagrams are observed which are expected within the Standard Model. Missing transverse momentum and visible energy distributions for the [Formula: see text] final state indicate some further possibilities of removing background for Higgs searches. A suggestion for an approximate treatment of the reaction [Formula: see text] is presented so that much computer time can be saved in Monte Carlo simulations.

SCALAR TOP PRODUCTION VIA BOSON-GLUON FUSION AT HERA

1992 ◽  
Vol 07 (14) ◽  
pp. 1209-1218 ◽  
Author(s):  
TETSURO KOBAYASHI ◽  
TADASHI KON ◽  
KEIICHIRO NAKAMURA ◽  
TAKESHI SUZUKI
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Top Quark ◽  
Gluon Fusion ◽  
Top Quarks ◽  
Tree Level ◽  
Mixing Angle ◽  
Light Scalar ◽  
Scalar Top ◽  
Level Calculation

We investigate the production of the light scalar top quark [Formula: see text] via boson-gluon fusion at ep collider HERA, based on the minimal supersymmetric standard model. The cross-section is obtained by both an exact tree level calculation and the Weizsäcker-Williams approximation. It is shown that the total cross-section is larger than 0.1pb if [Formula: see text] and does not depend on the mixing angle θt of scalar top quarks. This enables us to search a possible region of parameters for existence of light scalar top at HERA in a wider parameter space [Formula: see text] than LEP.

scholarly journals HIGGS BOSON PRODUCTION UNDER THE RESONANCE THRESHOLD AT LEP II

1996 ◽  
Vol 11 (28) ◽  
pp. 5015-5026 ◽  
Author(s):  
E. BOOS ◽  
M. DUBININ ◽  
L. DUDKO
Keyword(s):  
Higgs Boson ◽  
Tree Level ◽  
Boson Production ◽  
Higgs Boson Production ◽  
Quark Fragmentation ◽  
Complete Tree ◽  
B Quark

We consider the possibility of Higgs boson detection at LEP II under the resonance threshold [Formula: see text] in the framework of complete tree level approach to the calculation of the [Formula: see text] amplitude, simulating b quark fragmentation to hadrons and taking into account typical detector properties. At the energy below the 2mZ threshold [Formula: see text] Higgs boson production under the mH + mZ threshold is almost background free.

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