First observation of the decay B+ → π+ μ+ μ-

A discovery of the rare decay B+ → π+ μ+ μ- is presented. This decay is observed for the first time, with 5.2 σ significance. The observation is made using pp collision data, corresponding to an integrated luminosity of 1.0 fb -1, collected with the LHCb detector. The measured branching fraction is (2.3 ± 0.6 (stat.) ± 0.1 (syst.))×10-8, and the ratio of the B+ → π+ μ+ μ- and B+ → K+ μ+ μ- branching fractions is measured to be 0.053 ± 0.014 (stat.) ± 0.001 (syst.).

Title:

First observation of the decay B+ → π+ μ+ μ-
Authors: Aaij, Roel
Beteta, C. Abellán
Adametz, Aleksandra , ...
Keywords: Hadron
Decay
Energy
LHCb detector
Physics
Issue Date: 2012
Publisher: H. : ĐHQGHN
Abstract: A discovery of the rare decay B+ → π+ μ+ μ- is presented. This decay is observed for the first time, with 5.2 σ significance. The observation is made using pp collision data, corresponding to an integrated luminosity of 1.0 fb -1, collected with the LHCb detector. The measured branching fraction is (2.3 ± 0.6 (stat.) ± 0.1 (syst.))×10-8, and the ratio of the B+ → π+ μ+ μ- and B+ → K+ μ+ μ- branching fractions is measured to be 0.053 ± 0.014 (stat.) ± 0.001 (syst.).
Description: Journal of High Energy Physics 2012(12),125
URI: http://repository.vnu.edu.vn/handle/VNU_123/27469
Appears in Collections:Bài báo của ĐHQGHN trong Scopus

Nhận xét

Đăng nhận xét

Bài đăng phổ biến từ blog này

Nhu cầu đối với hoạt động công tác xã hội trong việc nâng cao kiến thức chăm sóc sức khỏe sinh sản vị thành niên ở nông thôn (Nghiên cứu trường hợp xã Lam Điền, huyện Chương Mỹ, thành phố Hà Nội)

Title:  Nhu cầu đối với hoạt động công tác xã hội trong việc nâng cao kiến thức chăm sóc sức khỏe sinh sản vị thành niên ở nông thôn (Nghiên cứu trường hợp xã Lam Điền, huyện Chương Mỹ, thành phố Hà Nội) Authors:  Đặng, Thùy Linh Keywords:  Công tác xã hội;Sức khỏe sinh sản Issue Date:  2016 Publisher:  H.: ĐHKHXH&NV Description:  97 tr. URI:  http://repository.vnu.edu.vn/handle/VNU_123/33919 Appears in Collections: Luận văn - Luận án (LIC)
Đọc thêm

Measurement of the isospin asymmetry in B → K (*)μ +μ - decays

The isospin asymmetries of B → K (*)μ +μ - decays and the partial branching fractions of B 0 → K 0μ +μ - and B +→ K *+μ +μ - are measured as a function of the di-muon mass squared q 2 using an integrated luminosity of 1.0fb -1 collected with the LHCb detector. The B → Kμ +μ - isospin asymmetry integrated over q 2 is negative, deviating from zero with over 4 σ significance. The B → K *μ +μ - decay measurements are consistent with the Standard Model prediction of negligible isospin asymmetry. The observation of the decay B 0 → K s 0μ +μ - is reported with 5.7 σ significance. Assuming that the branching fraction of B 0 → K 0μ +μ - is twice that of B 0 → K s 0μ +μ -, the branching fractions of B 0 → K 0μ +μ - and B → K *+μ +μ - are found to be (0.31 +0.07 -0.06) × 10 -6 and (1.16 ±0.19) × 10 -6, respectively. Title:  Measurement of the isospin asymmetry in B → K (*)μ +μ - decays Authors:  Aaij, Roel Abellán Beteta, C. Adametz, Aleksandra Keywords:  Hadron ...
Đọc thêm

Biomass estimation of Sonneratia caseolaris (l.) Engler at a coastal area of Hai Phong city (Vietnam) using ALOS-2 PALSAR imagery and GIS-based multi-layer perceptron neural networks

Hình ảnh
This study tested the use of machine learning techniques for the estimation of above-ground biomass (AGB) of Sonneratia caseolaris in a coastal area of Hai Phong city, Vietnam. We employed a GIS database and multi-layer perceptron neural networks (MLPNN) to build and verify an AGB model, drawing upon data from a survey of 1508 mangrove trees in 18 sampling plots and ALOS-2 PALSAR imagery. We assessed the model’s performance using root-mean-square error, mean absolute error, coefficient of determination (R2), and leave-one-out cross-validation. We also compared the model’s usability with four machine learning techniques: support vector regression, radial basis function neural networks, Gaussian process, and random forest. The MLPNN model performed well and outperformed the machine learning techniques. The MLPNN model-estimated AGB ranged between 2.78 and 298.95 Mg ha−1 (average = 55.8 Mg ha−1); below-ground biomass ranged between 4.06 and 436.47 Mg ha−1 (average = 81.47 M...
Đọc thêm