Flavor Structure in F-theory Compactifications

F-theory is one of frameworks in string theory where supersymmetric grand unification is accommodated, and all the Yukawa couplings and Majorana masses of right-handed neutrinos are generated. Yukawa couplings of charged fermions are generated at codimension-3 singularities, and a contribution from a given singularity point is known to be approximately rank 1. Thus, the approximate rank of Yukawa matrices in low-energy effective theory of generic F-theory compactifications are minimum of either the number of generations N_gen = 3 or the number of singularity points of certain types. If there is a geometry with only one E_6 type point and one D_6 type point over the entire 7-brane for SU(5) gauge fields, F-theory compactified on such a geometry would reproduce approximately rank-1 Yukawa matrices in the real world. We found, however, that there is no such geometry. Thus, it is a problem how to generate hierarchical Yukawa eigenvalues in F-theory compactifications. A solution in the literature so far is to take an appropriate factorization limit. In this article, we propose an alternative solution to the hierarchical structure problem (which requires to tune some parameters) by studying how zero mode wavefunctions depend on complex structure moduli. In this solution, the N_gen x N_gen CKM matrix is predicted to have only N_gen entries of order unity without an extra tuning of parameters, and the lepton flavor anarchy is predicted for the lepton mixing matrix. We also obtained a precise description of zero mode wavefunctions near the E_6 type singularity points, where the up-type Yukawa couplings are generated.Comment: 148 page

Froggatt-Nielsen models from E8 in F-theory GUTs

This paper studies F-theory SU(5) GUT models where the three generations of the standard model come from three different curves. All the matter is taken to come from curves intersecting at a point of enhanced E8 gauge symmetry. Giving a vev to some of the GUT singlets naturally implements a Froggatt-Nielsen approach to flavour structure. A scan is performed over all possible models and the results are filtered using phenomenological constraints. We find a unique model that fits observations of quark and lepton masses and mixing well. This model suffers from two drawbacks: R-parity must be imposed by hand and there is a doublet-triplet splitting problem.Comment: 42 pages; v2:journal version; v3:corrected typo in neutrino masse

BRIEF REPORT: Brief Instrument to Assess Geriatrics Knowledge of Surgical and Medical Subspecialty House Officers

Initiatives are underway to increase geriatrics training in nonprimary care disciplines. However, no validated instrument exists to measure geriatrics knowledge of house officers in surgical specialties and medical subspecialties. METHODS : A 23-item multiple-choice test emphasizing inpatient care and common geriatric syndromes was developed through expert panels and pilot testing, and administered to 305 residents and fellows at 4 institutions in surgical disciplines (25% of respondents), emergency medicine (29%), medicine subspecialties (19%), internal medicine (12%), and other disciplines (15%). RESULTS : Three items decreased internal reliability. The remaining 20 items covered 17 topic areas. Residents averaged 62% correct on the test. Internal consistency was appropriate (Cronbach's Α coefficient=0.60). Validity was supported by the use of expert panels to develop content, and by overall differences in scores by level of training ( P <.0001) and graded improvement in test performance, with 58%, 63%, 62%, and 69% correct responses among HO1, HO2, HO3, and HO4s, respectively. CONCLUSIONS : This reliable, valid measure of clinical geriatrics knowledge can be used by a wide variety of surgical and medical graduate medical education programs to guide curriculum reform or evaluate program performance to meet certification requirements. The instrument is now available on the web.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73902/1/j.1525-1497.2006.00433.x.pd

Gluino Decay as a Probe of High Scale Supersymmetry Breaking

A supersymmetric standard model with heavier scalar supersymmetric particles has many attractive features. If the scalar mass scale is O(10 - 10^4) TeV, the standard model like Higgs boson with mass around 125 GeV, which is strongly favored by the LHC experiment, can be realized. However, in this scenario the scalar particles are too heavy to be produced at the LHC. In addition, if the scalar mass is much less than O(10^4) TeV, the lifetime of the gluino is too short to be measured. Therefore, it is hard to probe the scalar particles at a collider. However, a detailed study of the gluino decay reveals that two body decay of the gluino carries important information on the scalar scale. In this paper, we propose a test of this scenario by measuring the decay pattern of the gluino at the LHC.Comment: 29 pages, 9 figures; version published in JHE

(De)Constructing a Natural and Flavorful Supersymmetric Standard Model

Using the framework of deconstruction, we construct simple, weakly-coupled supersymmetric models that explain the Standard Model flavor hierarchy and produce a flavorful soft spectrum compatible with precision limits. Electroweak symmetry breaking is fully natural; the mu-term is dynamically generated with no B mu-problem and the Higgs mass is easily raised above LEP limits without reliance on large radiative corrections. These models possess the distinctive spectrum of superpartners characteristic of "effective supersymmetry": the third generation superpartners tend to be light, while the rest of the scalars are heavy.Comment: 36 pages, 4 figures ; v2: references added, expanded discussion of FCNC

6D supergravity without tensor multiplets

We systematically investigate the finite set of possible gauge groups and matter content for N = 1 supergravity theories in six dimensions with no tensor multiplets, focusing on nonabelian gauge groups which are a product of SU(N) factors. We identify a number of models which obey all known low-energy consistency conditions, but which have no known string theory realization. Many of these models contain novel matter representations, suggesting possible new string theory constructions. Many of the most exotic matter structures arise in models which precisely saturate the gravitational anomaly bound on the number of hypermultiplets. Such models have a rigid symmetry structure, in the sense that there are no moduli which leave the full gauge group unbroken.Comment: 31 pages, latex; v2, v3: minor corrections, references adde

COVID sex lives : survey 1 report

This report presents initial findings from the first survey of Covid Sex Lives project. Public health measures to mitigate the spread of coronavirus are translated into media messaging by organisations that target the health of different groups. This research studies the experiences of Men who have Sex with Men (MSM), during the COVID-19 pandemic in the United Kingdom. Our focus is on uses of dating and hook up apps, sexual activity and how and how this has changed during the pandemic as restrictions such as social distancing and lockdowns have been introduced. We are conducting this research with a view to help improve policy and practice around MSM sexual wellbeing and public health messaging, shed light on what to look for where MSM are concerned, and provide learning about COVID public health messaging that will benefit MSM and the general population. The research is a collaboration between the University of Salford, Kings College London, Birmingham City University and Newcastle University and is funded by UKRI. You can find out more here: https://hub.salford.ac.uk/health-and-society-research/public-healthmessaging- during-the-covid-pandemic-dating-app-usage-and-sexual-wellbeing-among-menwho- have-sex-with-men

COVID sex lives : survey 2 report

This report presents initial findings from the second survey of Covid Sex Lives project. Public health measures to mitigate the spread of coronavirus are translated into media messaging by organisations that target the health of different groups. This research studies the experiences of Men who have Sex with Men (MSM), during the COVID-19 pandemic in the United Kingdom. Our focus is on uses of dating and hook up apps, sexual activity and how this has changed during the pandemic as restrictions such as social distancing and lockdowns have been introduced. We are conducting this research with a view to help improve policy and practice around MSM sexual wellbeing and public health messaging, shed light on what to look for where MSM are concerned, and provide learning about COVID public health messaging that will benefit MSM and the general population. The research is a collaboration between the University of Salford, Kings College London, Birmingham City University and Newcastle University and is funded by UKRI. You can find out more and view our past reports here: https://hub.salford.ac.uk/health-and-society-research/public-health-messaging-during-the-covid-pandemic-dating-app-usage-and-sexual-wellbeing-among-men-who-have-sex-with-men