The sum rules related to thick braneworlds are constructed, in order to encompass Gauss-Bonnet terms. The generation of thick branes is hence proposed in a periodic extra dimension scenario, what circumvents the Gibbons-Kallosh-Linde no-go theorem in this context.
We propose a type of non-anticommutative superspace, with the interesting property of relating to Lee-Wick type of higher derivatives theories, which are known for their interesting properties, and have lead to proposals of phenomenologicaly viable h
igher derivatives extensions of the Standard Model. The deformation of superspace we consider does not preserve supersymmetry or associativity in general; however, we show that a non-anticommutative version of the Wess-Zumino model can be properly defined. In fact, the definition of chiral and antichiral superfields turns out to be simpler in our case than in the well known ${cal N}=1/2$ supersymmetric case. We show that, when the theory is truncated at the first nontrivial order in the deformation parameter, supersymmetry is restored, and we end up with a well known Lee-Wick type of higher derivative extension of the Wess-Zumino model. Thus we show how non-anticommutative could provide an alternative mechanism for generation of these kind of higher derivative theories.
Very recently it was predicted the existence of a charged state near the $D_sbar{D}^*/D^*_sbar{D}$ threshold. This state, that we call $Z_{cs}^+$, would be the strange partner of the recently observed $Z_c^pm(3900)$. Using standard techniques of QCD
sum rules, we evaluate the three-point function for the vertices $Z_{cs}^+ , J/psi , K^+$, $Z_{cs}^+ , eta_c , K^{*+}$ and $Z_{cs}^+ , D_s^+bar{D}^{*0}$ and we make predictions for the corresponding decay widths in these channels.
Using a superfield generalization of the tadpole method, we study the one-loop effective potential for a Wess Zumino model modified by a higher-derivative term, inspired by the Lee-Wick model. The one-loop K{a}hlerian potential is also obtained by ot
her methods and compared with the effective potential.
Using the QCD sum rules we test if the new narrow structure, the X(4350) recently observed by the Belle Collaboration, can be described as a $J^{PC}=1^{-+}$ exotic $D_s^*D_{s0}^*$ molecular state. We consider the contributions of condensates up to di
mension eight, we work at leading order in $alpha_s$ and we keep terms which are linear in the strange quark mass $m_s$. The mass obtained for such state is $m_{D_s^*{D}_{s0}^*}=(5.05pm 0.19)$ GeV. We also consider a molecular $1^{-+}, D^{*}{D}_0^{*}$ current and we obtain $m_{D^*{D}_0^*}=(4.92pm 0.08)$ GeV. We conclude that it is not possible to describe the X(4350) structure as a $1^{-+} D_s^*{D}_{s0}^*$ molecular state.
