On the interpretation of a possible ∼ 750 GeV particle decaying into γγ

We consider interpretations of the recent ∼ 3σ reports by the CMS and ATLAS collaborations of a possible X (∼750 GeV) state decaying into γγ final states. We focus on the possibilities that this is a scalar or pseudoscalar electroweak isoscalar state produced by gluon-gluon fusion mediated by loops of heavy fermions. We consider several models for these fermions, including a single vector-like charge 2/3 T quark, a doublet of vector-like quarks (T, B), and a vector-like generation of quarks, with or without leptons that also contribute to the X → γγ decay amplitude. We also consider the possibility that X (750) is a dark matter mediator, with a neutral vector-like dark matter particle. These scenarios are compatible with the present and prospective direct limits on vector-like fermions from LHC Runs 1 and 2, as well as indirect constraints from electroweak precision measurements, and we show that the required Yukawa-like couplings between the X particle and the heavy vector-like fermions are small enough to be perturbative so long as the X particle has dominant decay modes into gg and γγ. The decays X → ZZ, Zγ and W+W− are interesting prospective signatures that may help distinguish between different vector-like fermion scenarios

On Naturalness of the MSSM and NMSSM

With a bottom-up approach, we consider naturalness in the MSSM and NMSSM. Assuming the light stops, the LHC gluino search implies that the degree of fine tuning in both models is less than 2.5%. Taking the LHC hints for the SM-like Higgs boson mass m_h\sim125 GeV seriously, we find that naturalness will favor the NMSSM. We study the Higgs boson mass for several scenarios in the NMSSM: (1) A large \lambda and the doublet-singlet Higgs boson mixing effect pushing upward or pulling downward m_h. The former case can readily give the di-photon excess of the Higgs boson decay whereas the latter case can not. However, we point out that the former case has a new large fine-tuning related to strong \lambda-RGE running effect and vacuum stability. (2) A small \lambda and the mixing effect pushing m_h upward. Naturalness status becomes worse and no significant di-photon excess can be obtained. In these scenarios, the lightest supersymmetric particle (LSP) as a dark matter candidate is strongly disfavored by the XENON100 experiment. Even if the LSP can be a viable dark matter candidate, there does exist fine-tuning. The above naturalness evaluation is based on a high mediation scale for supersymmetry breaking, whereas for a low mediation scale, fine-tuning can be improved by about one order.Comment: JHEP version, adding some comments/references and improving Englis

Effects of Pleiotrophin on endothelial and inflammatory cells: Pro-angiogenic and anti-inflammatory properties and potential role for vascular bio-prosthesis endothelialization

Purpose: One of the limitations emerged with both synthetic and degradable vascular grafts is the lack of endothelialization after implantation that is known to be the main reason leading to unfavourable outcomes. It emerges the need to find new strategies to promote a rapid endothelialization of the scaffold. Pleiotrophin is a growth/differentiation cytokine for various cell type. We here evaluated the effect of Pleiotrophin on endothelial cells (EC), monocytes and macrophages that have been shown as key cells promoting neovascularization. Material/Methods: Eahy926 endothelial cells, THP-1 monocytes and PMA-differentiated macrophages were treated with Pleiotrophin (10 and 100 ng/ml).VEGF, Flk-1, Nrp-1, COX-2, ICAM-1 and TGF\u3b2 expression were detected by Western Blot, IL-10, MCP-1 and TNF\uf061 levels by ELISA. Chemotaxis was performed in Boyden chambers. Wound healing was performed by scratch wound assay. Results: Pleiotrophin induces in EC the expression of VEGF and its receptors Flk-1 and Nrp-1 and improves the migratory capacity. In THP-1 monocytes, Pleiotrophin induces the expression of VEGF and its receptor Nrp-1 and decreases the levels of COX-2 and TNF\u3b1. In PMA-differentiated macrophages COX-2 expression was significantly reduced by Pleiotrophin, while IL-10 and TGF\u3b2 were increased. Conclusions: Pleiotrophin acts as an angiogenesis \u2018driver\u2019 by promoting the creation of a pro-angiogenic environment, a migratory behaviour in EC and a pro-regenerative alternative phenotype in macrophages. Our results suggest that Pleiotrophin might be considered for vascular prosthesis engineering

Twelve-year Follow-up Post–Thoracic Endovascular Repair in Type B Aortic Dissection Shown by Three-dimensional Printing

Background: Thoracic endovascular repair (TEVAR) is currently considered the therapy of choice for complicated type B acute aortic dissection (TBAAD). Although several papers have reported good outcomes at short- and medium-term follow-up, some questions still remain regarding the long-term durability and re-intervention rate during follow-up. Methods: We describe a case of a patient originally treated with TEVAR for TBAAD complicated by impending aortic rupture. Results: Endovascular repair successfully excluded the flow through the primary entry tear but during the 12-year follow-up period the patient experienced several complications and re-interventions. Various full-size three-dimensional (3D) models of the patient-specific vasculature were printed to better explain the different interventional interventions over the 12 years of follow-up and as a hands-on tool for medical education. Conclusions: The present case report, involving long-term follow-up, provides an example of the effectiveness and the safety of TEVAR for the treatment of complicated TBAAD shown at short and medium-term follow-up. However, the long-term complications that were observed in this patient during follow-up support the importance of lifelong CTA surveillance. Furthermore, this study confirms the capability of 3D printing technology as a powerful tool to support communication with patients and residents’ education through the physical analysis of the real cases