Difference between revisions of "Master student Projects"

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=== Projects for Master students in the Nikhef B-physics (LHCb) group 2017 - 2018===
 
=== Projects for Master students in the Nikhef B-physics (LHCb) group 2017 - 2018===
  
date: Dec 2017
+
date: April 2018
  
 
This is an overview with all available Master student projects in the Nikhef B-physics (LHCb) group.
 
This is an overview with all available Master student projects in the Nikhef B-physics (LHCb) group.
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{| border="1" cellpadding="2" cellspacing="0"  
 
{| border="1" cellpadding="2" cellspacing="0"  
 
|-  
 
|-  
! style="background:#3399ff;" | <font color=#ffffff> 2) Measurement of BR(Lb -> p Ds-) </font>  
+
! style="background:#3399ff;" | <font color=#ffffff> 2) Measurement of BR(B0 ->Ds+ Ds-) </font>  
 
|}
 
|}
  
''' Supervisors:''' Niels Tuning (staff), Lennaert Bel (PhD) , Mick Mulder (PhD)  
+
''' Supervisors:''' Sevda Esen (postdoc), Niels Tuning (staf), Michele Veronesi (PhD)  
  
 
''' Research description: '''
 
''' Research description: '''
  
This project aims to discover the branching fraction of the decay Lb->p Ds+.
+
This project aims to discover the branching fraction of the decay B0->Ds- Ds+.
The decay Lb->p Ds+ is quite rare, because it occurs through the transition of a b-quark
+
The decay B0->Ds- Ds+ is quite rare, because it occurs through the exchange of a W-boson between the
to a u-quark. It has not been measured yet (although some LHCXb colleagues claim to have seen it in the past).
+
b and the d-quark of the B0-meson.
 +
This decay proceeds via Cabibbo-suppressed W-exchange and
 +
has not yet been observed; theoretical calculations predict
 +
a branching fraction at the order of 10^-5 with a best
 +
experimental upper limit of 3.6x10^-5.
  
This decay is interesting, because <br>
+
A measurement of the decay rate of B0 -> Ds+Ds- relative to
1) It is sensitive to the CKM-element Vub, which determination is heavily debated.<br>
+
that of B0 -> D+D- can provide an estimate of the W-exchange contribution
2) It can quantify non-factorisable QCD effects in b-baryon decays.
+
to the latter decay, a crucial piece of information for extracting
 +
the CKM angle gamma from B0 ->D(*)D(*).
  
The decay is closely related to B0->pi-Ds+, which proceeds through a similar
+
The aim is to determine the relative branching fraction of  B0->Ds+Ds- with respect to B0->Ds+D- decays
Feynman diagram. Also the final state of B0->pi-Ds+ is almost identical to Lb->p Ds+.
+
(which has the best known branching ratio at present, (7.2 +- 0.8)x10^-3),
The aim is to determine the relative branching fraction of  Lb->pDs+ with respect to B0->D+pi- decays,
+
in close collaboration with the PhD.
in close collaboration with the PhD (who will study BR(B0->pi-Ds+)/BR(B0->D+pi-) ).
 
 
The aim is that this project results in a journal publication on behalf of the LHCb collaboration.
 
The aim is that this project results in a journal publication on behalf of the LHCb collaboration.
 
For this project computer skills are needed.
 
For this project computer skills are needed.
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''' Relevant information: '''
 
''' Relevant information: '''
  
[1] R.Aaij et al. [LHCb Collaboration],  
+
[1] M.Jung and S.Schacht,
``Study of the kinematic dependences of Lambda_b production in pp collisions and a measurement of the Lambda_b->Lambda_c pi branching fraction'',
+
"Standard Model Predictions and New Physics Sensitivity in B ? DD Decays"
JHEP 08 (2014) 143 [arXiv:1405.6842 [hep-ex]].
+
https://arxiv.org/pdf/1410.8396.pdf
  
[2] R.Aaij et al. [LHCb Collaboration],  
+
[2] L.Bel, K.de Bruyn, R. Fleischer, M.Mulder, N.Tuning,
``Determination of the branching fractions of B0s->DsK and B0->DsK'',
+
"Anatomy of B ? DD Decays"
JHEP 05 (2015) 019 [arXiv:1412.7654 [hep-ex]].
+
https://arxiv.org/pdf/1505.01361.pdf
  
[3] R. Fleischer, N. Serra and N. Tuning,
+
[3] A.Zupanc et al [Belle Collaboration]
``Tests of Factorization and SU(3) Relations in B Decays into Heavy-Light Final States'',
+
"Improved measurement of B0 ? Ds?D+ and search for B0 ? Ds+Ds? at Belle"
Phys. Rev. D 83, 014017 (2011) [arXiv:1012.2784 [hep-ph]].
+
https://arxiv.org/pdf/hep-ex/0703040.pdf
  
[4] K. de Bruyn, R. Fleischer, R. Knegjens, M. Merk, M. Schiller and N. Tuning,
+
[4] B.Aubert et al. [Babar Collaboration]
``Exploring Bs -> Ds(*)K Decays in the Presence of a Sizable Width Difference Delta Gamma_s'',
+
"Search for the W-exchange decays B0 ? D(?)?D(?)+"
Nucl. Phys. B 868, 351 (2013) [arXiv:1208.6463 [hep-ph]].
+
https://arxiv.org/pdf/hep-ex/0510051.pdf
 +
 
 +
[5] R.Aaij et al. [LHCb Collaboration],
 +
"First observations of B0s ? D+D?, Ds+D? and D0D0 decays"
 +
https://arxiv.org/pdf/1302.5854.pdf
  
  

Revision as of 15:36, 11 April 2018