Forward W + c, b-jet and Top Measurements with LHCb

Inclusive c and b-jet tagging algorithms have been developed to utilize the excellent secondary vertex reconstruction and resolution capabilities of the LHCb detector. The validation and performance of these tagging algorithms are reported using the full run 1 LHCb dataset at 7 and 8 TeV. Jet-tagging has been applied to muon+jet final states to measure both the W+c,b-jet charge asymmetries and the ratios of W+c,b-jet to W+jet and W+jet to Z+jet production. The forward top production cross-section is also measured using the muon+b-jet final. All results are found to be consistent with standard model predictions.Comment: 8 pages, 5 figures, presentation at the DPF 2015 Meeting of the American Physical Society Division of Particles and Fields, Ann Arbor, Michigan, August 4-8, 201

Soft QCD Measurements at LHCb

Studies in the forward region of charged particle multiplicity and density, as well as energy flow, are presented. These measurements are performed using data from proton-proton collisions at a center-of-mass energy of 7 TeV, collected with the LHCb detector. The results are compared to predictions from a variety of Monte Carlo event generators and are used to test underlying event and hadronization models as well as the performance of event generator tunes in the forward region.Comment: 6 pages, 10 figure

WW and ZZ Production in the Forward Region with LHCb

Results for $W$ and $Z$ boson production from $pp$ collisions at $\sqrt{s} = 7$ TeV in the LHCb experiment are presented. Due to LHCb's unique forward acceptance in pseudorapidity of $2.0 \leq \eta \leq 4.5$ these results are a test of the Standard Model in the forward region, and can be used to better constrain parton density functions in the low $x$ kinematic regime.Comment: 4 pages, 6 figures, PANIC1

Z→ττZ \to \tau\tau and W→τντW \to \tau\nu_\tau Cross-Sections at the LHC

Measurements of the $Z \to \tau\tau$ and $W \to \tau\nu_\tau$ cross-sections at the LHC with data taken at $\sqrt{s} = 7$ TeV are reported for the ATLAS, CMS, and LHCb experiments. All results are found to agree with the Standard Model.Comment: 4 pages, 1 figur

Mutations of Laurent Polynomials and Flat Families with Toric Fibers

We give a general criterion for two toric varieties to appear as fibers in a flat family over the projective line. We apply this to show that certain birational transformations mapping a Laurent polynomial to another Laurent polynomial correspond to deformations between the associated toric varieties

Fano schemes of determinants and permanents

Let $D_{m,n}^r$ and $P_{m,n}^r$ denote the subschemes of $\mathbb{P}^{mn-1}$ given by the $r\times r$ determinants (respectively the $r\times r$ permanents) of an $m\times n$ matrix of indeterminates. In this paper, we study the geometry of the Fano schemes $\mathbf{F}_k(D_{m,n}^r)$ and $\mathbf{F}_k(P_{m,n}^r)$ parametrizing the $k$-dimensional planes in $\mathbb{P}^{mn-1}$ lying on $D_{m,n}^r$ and $P_{m,n}^r$, respectively. We prove results characterizing which of these Fano schemes are smooth, irreducible, and connected; and we give examples showing that they need not be reduced. We show that $\mathbf{F}_1(D_{n,n}^n)$ always has the expected dimension, and we describe its components exactly. Finally, we give a detailed study of the Fano schemes of $k$-planes on the $3\times 3$ determinantal and permanental hypersurfaces.Comment: 43 pages; v2 minor revisions. To appear in AN