2020/06/30 by Hieu Minh Tran, Yoshimasa Kurihara
Computer Science · Physics and Astronomy · #Collider #Computational Physics and Python Applications #Form factor (electronics) #Magnetic form factor #Measure (data warehouse) #Muon #Particle physics theoretical and experimental studies #Physics beyond the Standard Model #Position (finance) #Quantum Chromodynamics and Particle Interactions #Range (aeronautics) #Standard Model (mathematical formulation) #hep-ph
paper · pdf · doi:10.1140/epjc/s10052-021-08846-x
18 pages, 6 figures
openalex created_date 2020/06/05 · arxiv created 2020/06/30 · openalex publication_date 2021/02/01 · arxiv updated 2021/02/24 · openalex updated_date 2026/08/05
Abstract The deviation between the prediction based on the standard model and the measurement of the muon g-2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>g</mml:mi> <mml:mo>-</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:math> is currently at 3-4 σ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>3</mml:mn> <mml:mo>-</mml:mo> <mml:mn>4</mml:mn> <mml:mi>σ</mml:mi> </mml:mrow> </mml:math> . If this discrepancy is attributable to new physics, it is expected that the new contributions to the tau g-2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>g</mml:mi> <mml:mo>-</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:math> even larger than those of muon due to its large mass. However, it is much more difficult to directly measure the tau g-2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>g</mml:mi> <mml:mo>-</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:math> because of its short lifetime. In this report, we consider the effect of the tau g-2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>g</mml:mi> <mml:mo>-</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:math> at e-e+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>-</mml:mo> </mml:msup> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:mrow> </mml:math> colliders using a model independent approach. Using the tau pair production channel at the Large Electron Position Collider (LEP), we have determined the allowed range for the new physics contribution of the tau g-2 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>g</mml:mi> <mml:mo>-</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:math> assuming a q-square-dependence ansatz for the magnetic form factor. We also investigated the prospect at future e+e- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>-</mml:mo> </mml:msup> </mml:mrow> </mml:math> colliders, such as International Linear Collider, the Compact Linear Collider, the Future Circular e+e- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mi>e</mml:mi> <mml:mo>-</mml:mo> </mml:msup> </mml:mrow> </mml:math> Collider, and Circular Electron Positron Collider, and determined the expected allowed range for the new physics contribution to the tau anomalous magnetic moment. The best limits are about 4-5 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>4</mml:mn> <mml:mo>-</mml:mo> <mml:mn>5</mml:mn> </mml:mrow> </mml:math> times more severe than the LEP one due to the beam polarization and the high luminosities at future colliders.