Searching for an axion-like particle at the Large Hadron Collider

Axion-like particles are an important part of the spectrum of anomalous gauge theories involving modified mechanisms of cancellation of the gauge anomalies. Among these are intersecting brane models, which are characterized by the presence of one physical axion. We overview a recent study of their supersymmetric construction and some LHC studies of the productions rates for a gauged axion

Comments on Anomaly Cancellations by Pole Subtractions and Ghost Instabilities with Gravity

We investigate some aspects of anomaly cancellation realized by the subtraction of an anomaly pole, stressing on some of its properties in superspace. In a local formulation these subtractions can be described in terms of a physical scalar, an axion and related ghosts. They appear to be necessary for the unitarization of the theory in the ultraviolet, but they may generate an infrared instability of the corresponding effective action, signalled by ghost condensation. In particular the subtraction of the superanomaly multiplet by a pole in superspace is of dubious significance, due to the different nature of the chiral and conformal anomalies. In turn, this may set more stringent constraints on the coupling of supersymmetric theories to gravity.Comment: 18 pages. Revised version. To appear in "Classical and Quantum Gravity

Axion and neutralinos from supersymmetric extensions of the Standard Model with anomalous U ( 1 ) 's

We analyze the conditions under which some supersymmetric generalizations of a class of models descending from string theory allow an axion in the physical spectrum, due to the presence of anomalous abelian gauge interactions. The gauge structure of these constructions involve the Stueckelberg supermultiplet and a supersymmetric version of the Wess-Zumino term for anomaly cancellation. While these conditions are not satisfied by the MSSM superpotential, we show that an axion-like particle appears in the spectrum if extra Standard Model singlets are present. We show that the minimal requirements are met by simple superpotentials in which the singlet superfield is charged under the anomalous U(1). The dark matter sector of these models include an axion and several neutralinos with an axino component.Comment: Phys.Lett.B Published version, 9 pages, 1 figur